Evidence Law in Australia
Introduction
The law of evidence in Australia operates under a bifurcated system. The majority of Australian jurisdictions have adopted the Uniform Evidence Acts (UEA), based on the Evidence Act 1995 (Cth) and the Evidence Act 1995 (NSW). The UEA is also in force in Victoria (since 2008), Tasmania (2001), the Australian Capital Territory (2011), and the Northern Territory (2013). However, Queensland, South Australia, and Western Australia have not adopted the uniform legislation and continue to apply the common law of evidence, supplemented by local statute. This division creates significant practical differences in the conduct of litigation across Australian jurisdictions, particularly in the treatment of hearsay, tendency and coincidence evidence, and the operation of judicial discretions.
Relevance: The Threshold Requirement
Under the uniform legislation, relevance is the foundational requirement for admissibility. Section 55 of the Evidence Act 1995 (Cth) provides that evidence is relevant if it could rationally affect (directly or indirectly) the assessment of the probability of a fact in issue. Relevancy is a low threshold — evidence need not be conclusive, it need only have some logical connection to a fact in dispute. If evidence is not relevant, it is inadmissible (s 56).
The uniform Acts then confer a series of discretions to exclude otherwise admissible evidence. Section 135 confers a general discretion to exclude evidence if its probative value is substantially outweighed by the danger of unfair prejudice, misleading or confusing the jury, or causing undue waste of time. Section 137 imposes a mandatory obligation on the court in criminal proceedings to exclude prosecution evidence if its probative value is outweighed by the danger of unfair prejudice. The High Court in R v Baukham [2019] clarified that the test under s 137 requires a balancing exercise in which probative value is assessed according to the capacity of the evidence to rationally affect proof of a fact in issue, assuming the jury gives the evidence its maximum probative force.
The Hearsay Rule
The hearsay rule (s 59 of the uniform Acts) renders inadmissible evidence of a previous representation made by a person to prove the existence of a fact that the person intended to assert. The rule is based on the concern that hearsay evidence is unreliable because it cannot be tested through cross-examination of the original declarant. The uniform legislation nevertheless provides a comprehensive set of exceptions.
For civil proceedings, the most significant exception is first-hand hearsay (s 63), which permits evidence of a previous representation if the maker of the representation is not available to give evidence. Business records (s 69) are admissible as an exception to the hearsay rule, reflecting the reliability of records made in the ordinary course of business. In criminal proceedings, the exception for contemporaneous statements about a person’s health, feelings, or state of mind (s 66) permits hearsay evidence of a representation made shortly after the occurrence of the asserted fact. The prior inconsistent statement provisions (s 43) allow a witness’s prior inconsistent statement to be admitted as evidence of the facts asserted in the statement, not merely to impeach the witness’s credibility.
Common law jurisdictions apply the hearsay rule in a different form, with exceptions developed incrementally through case law. The common law recognizes the res gestae exception, the dying declarations exception, and exceptions for business and public records, but these are narrower and less systematically structured than the UEA exceptions.
The Opinion Rule
The opinion rule (s 76) provides that evidence of an opinion is not admissible to prove the existence of a fact about the existence of which the opinion was expressed. The rule distinguishes between evidence of fact (what a witness perceived) and evidence of opinion (what a witness inferred). The principal exception is expert opinion (s 79), which permits opinion evidence where the opinion is wholly or substantially based on the witness’s specialised knowledge based on training, study, or experience. The High Court’s decision in HG v The Queen (1999) established the requirement for a transparent chain of reasoning connecting the expert’s specialised knowledge to the opinion expressed. In Dasreef Pty Ltd v Hawchar (2011), the High Court reinforced that the expert must demonstrate how their specialised knowledge applied to the facts of the case, rejecting the admission of bald assertions of expertise.
Tendency and Coincidence Evidence
The uniform legislation imposes stringent controls on tendency evidence (evidence that a person has a tendency to act in a particular way — s 97) and coincidence evidence (evidence that two or more events occurred in such a manner as to make it improbable that they occurred coincidentally — s 98). Both forms of evidence are inadmissible unless the court considers that the evidence would have significant probative value and the party seeking to adduce it has given reasonable notice. In criminal proceedings, further protections apply under s 101: tendency or coincidence evidence adduced by the prosecution cannot be used against the defendant unless its probative value substantially outweighs the danger of unfair prejudice to the defendant. In Hughes v The Queen (2017), the High Court clarified that the assessment of significant probative value requires consideration of the cogency of the evidence and the degree to which it supports the prosecution’s case.
The Credibility Rule
The credibility rule (s 102) generally excludes evidence adduced only to affect the credibility of a witness. However, the uniform Acts provide extensive exceptions. In cross-examination, a witness may be questioned about prior inconsistent statements, bias, and matters affecting their capacity to give reliable evidence. Evidence to re-establish credibility may be adduced if the credibility of a witness has been attacked. Section 108 permits evidence of a witness’s prior consistent statements if their credibility is attacked on the basis of recent invention or reconstruction.
Privilege and the Voir Dire
The uniform Acts codify several important privileges. The privilege against self-incrimination (s 128) permits a witness to object to giving evidence that may tend to prove that the witness has committed an offence. If the objection is upheld, the court must either require the witness to give the evidence (subject to a certificate preventing use of the evidence in subsequent proceedings) or determine that the interests of justice require the evidence to be given despite the privilege. Legal professional privilege (ss 118-119) protects confidential communications between lawyers and clients for the dominant purpose of giving or obtaining legal advice, or for use in existing or anticipated litigation.
The voir dire is a trial within a trial, conducted in the absence of the jury, in which the judge determines the admissibility of disputed evidence. Under s 189 of the uniform Acts, the court may hear evidence on a voir dire about the admissibility of evidence, including evidence about the circumstances in which an admission was made or the identification of a defendant.
Burden and Standard of Proof
In criminal proceedings, the prosecution bears the legal burden of proving every element of the offence beyond a reasonable doubt, reflecting the fundamental presumption of innocence. The defendant bears an evidential burden in relation to defences — the defendant must point to evidence sufficient to raise the defence, after which the prosecution must negative it beyond reasonable doubt. The standard of proof for the prosecution is beyond a reasonable doubt; for the defendant on any matter for which they bear the legal burden, the standard is the balance of probabilities. In civil proceedings, the standard of proof is the balance of probabilities, with the High Court in Briginshaw v Briginshaw (1938) establishing that the strength of evidence required may vary according to the seriousness of the allegations.
Conclusion
The law of evidence in Australia is undergoing a slow process of harmonisation through the incremental adoption of the uniform legislation. The UEA has brought greater consistency, codification, and accessibility to the law of evidence in the participating jurisdictions, but the continued divergence between UEA and common law jurisdictions means that practitioners must navigate two distinct evidentiary systems. The High Court continues to play a significant role in interpreting the uniform Acts, ensuring a degree of national coherence in the development of this fundamental area of procedural law.