Dietrich v The Queen is a 1992 High Court of Australia constitutional case which established that a person accused of serious criminal charges must be granted an adjournment until appropriate legal representation is provided if they are unrepresented through no fault of their own and proceeding would result in the trial being unfair.

Until the 5–2 opinion of Dietrich v The Queen, it was customary for those unable to afford legal representation to be forced to represent themselves at trial, even when facing serious criminal charges.

The case originated in the County Court of Victoria, where Olaf Dietrich, later known as Hugo Rich, had been convicted of importing a trafficable quantity of heroin.

The accused then requested for the High Court to hear an appeal on the ground that refusing to adjourn the trial meant he was unable to obtain legal representation, with this causing such prejudice that it constituted a miscarriage of justice.

[3] In a 4–1 decision, the High Court ruled that, while it was preferable for those accused of serious criminal charges to be represented, it was not a legal right and so there had been no miscarriage of justice.

It was argued that not granting adjournment meant a miscarriage of justice had occurred,[11] by refusing publicly funded legal representation meaning he proceeded to trial representing himself.

The appeal cited section 397 of the Crimes Act 1958 which, though now repealed, at the time said "every accused person shall be admitted after the close of the case for the prosecution to make full answer and defence thereto by legal counsel".

[16] Secondary to the argument for right to counsel was the assertion the originating judge should have adjourned the matter until Dietrich was able to provide legal representation, and the failure to do so caused a miscarriage of justice.

[20] In rejecting the second submission, the court noted such an approach is useful in interpreting legislation to resolve ambiguity but said to apply it in this circumstance would be to "declare a right which has hitherto never been recognised should now be taken to exist".

[21] On the third ground, the court accepted the cases cited by the defence team demonstrated United States law precluded an accused from imprisonment without access to publicly funded representation.

[28] In passing, Deane and Gaudron said the right to representation was in some circumstances constitutionally guaranteed by Chapter III, which requires judicial process and fairness to be observed.

After his release in October 2004, he again faced court for firearms charges and later for the murder of security guard Erwin Kastenberger during an armed robbery in Blackburn North on 8 March 2005.

[33] In the Supreme Court of Victoria on 12 June 2009, Dietrich was found guilty of the murder of Kastenberger,[34] and was jailed for life with a non-parole period of 30 years.

[39] An Australian Senate committee inquiry received multiple submissions saying the decision could result in legal-aid funds being redirected from civil or family law matters to criminal cases.

[40] Dietrich v The Queen restrains the way in which governments could provide assistance, promoting those accused of serious crimes as having a de facto right to public funding while those facing less-serious matters are refused.

[42] The Attorney-General asked courts to be realistic about applying principles from Dietrich v The Queen, leading to criticism of the government for interfering with the independence of the judiciary.

[42] For an accused person to succeed in applying for a stay based on the Dietrich v The Queen judgment, the applicant bears the onus of proving they are indigent, are charged with a serious offence, and cannot obtain legal representation through no fault of their own.

[46] Shortly after the decision was made, counsel for Dietrich noted several aspects of the ruling would need to be "worked out in practice", specifically the meaning of indigence.

At his trial for murder, former Melbourne underworld figure Carl Williams argued an adjournment was required because his preferred representation was unavailable.