Elizabeth Lee wrote to Shane Rattenbury on Friday, following what she described as "alarming" revelations the ACT Director of Public Prosecutions had accused police of aligning themselves with alleged rapist Bruce Lehrmann's defence.

In a letter to ACT chief police officer Neil Gaughan after Mr Lehrmann's trial was aborted because of juror misconduct, director Shane Drumgold SC alleged investigators had pressured him not to pursue the case.

Mr Drumgold also made the extraordinary claim alleged victim Brittany Higgins had felt "bullied" by police, who wanted her to withdraw her sexual assault complaint.

Mr Lehrmann, who denies raping Ms Higgins at Parliament House when the pair were federal Liberal Party staffers in 2019, will not face a retrial after Mr Drumgold dropped the case over fears for the alleged victim's mental health.

The increasingly public fallout has also included allegations of "political interference" in the criminal justice process.

This has concerned Ms Lee, who worked as a lawyer before entering politics and taking on the leadership of the Canberra Liberals.

"Unanswered questions surrounding these serious allegations and the trial could have a devastating and irreversible erosion of public confidence in our legal system," she wrote in her letter to Mr Rattenbury.

Ms Lee called for the Attorney-General to establish a "wide-ranging" board of inquiry, which is similar to a royal commission, to look into the growing number of issues being raised following the decision to discontinue Mr Lehrmann's case.

"A wide-ranging inquiry into the matter will provide an opportunity for a holistic review of not only these serious allegations but the entire prosecution, trial, and subsequent mistrial," the Opposition Leader said.

"This inquiry would provide confidence to the Canberra community, that the ACT government is dedicated to maintaining the highest and most robust legal standards."

Mr Rattenbury told The Canberra Times on Friday he would not rule out the establishment of a public inquiry into how the case had been handled, saying the government was "taking advice on the steps we'll take".

But the Attorney-General said it would be inappropriate to comment further because the matter had been referred to the Australian Commission for Law Enforcement Integrity, suggesting the government would wait until that body had investigated the matter before taking any action of its own.

Calls for a public inquiry are growing, however, with Ms Lee just the latest to support the idea.

Mr Drumgold raised his belief there should be a public inquiry when he wrote to Deputy Commissioner Gaughan, who has privately told police staff he is in favour of one.

"I welcome a public enquiry [sic] into all aspects of the matter including (but not limited to) the actions of police, the prosecution and defence, issues leading to delays in the trial, issues leading to the subsequent mistrial, the decision not to proceed and the associated allegations of contempt of court," Deputy Commissioner Gaughan wrote in an email to ACT Policing members on Thursday.

Australian Federal Police Association president Alex Caruana has also called for an examination of the matter, saying the union that represents ACT Policing officers "wholeheartedly" supports a full judicial inquiry.

MORE COURT AND CRIME COVERAGE:

"While Mr Drumgold has called for an inquiry into the actions of police, any inquiry, in the interests of impartiality and holism, must also assess the conduct of Mr Drumgold, the DPP, the ACT Victims of Crime Commissioner, and ACT Attorney-General Shane Rattenbury, as well as issues causing delays in the trial and subsequent mistrial," he said.

The police union boss was particularly keen for Mr Drumgold to explain why he had taken the case to trial when investigators believed there was not enough evidence and held concerns about how certain material had been obtained.

Mr Caruana has also signalled his intention to make a formal complaint to the Office of the Australian Information Commission and the ACT Ombudsman regarding the possibility Mr Drumgold broke the law when his office released his letter to The Guardian without redacting the personal details of police officers.

Both he and Deputy Commissioner Gaughan have said ACT Policing was not consulted about the letter's release under freedom of information laws.

Our journalists work hard to provide local, up-to-date news to the community. This is how you can continue to access our trusted content: