Probe into Joy Burch's office to assess whether there was criminal conduct, chief police officer confirms

But Assistant Commissioner Lammers also confirmed that, weeks into the investigation, police had no evidence of criminal conduct.

Ms Burch has been dumped from Labor's cabinet and moved to the backbench and her chief of staff has resigned over the affair, but the question of precisely what the police are investigating has not been spelled out.

Commissioner Lammers said the "evaluation", which he differentiated from an "investigation", was into matters reported in December.

It was reported then that police were looking into whether Ms Burch's chief of staff, Maria Hawthorne, had passed details of a confidential police briefing to Construction, Forestry, Mining and Energy Union boss Dean Hall.

Police are believed to have a recording of a conversation between the pair, given Mr Hall's union was being investigated by the trade unions royal commission at the time. Ms Hawthorne has admitted to criticising Assistant Commissioner Lammers in that conversation.

She has also released a list of questions police put to her in late January, through her lawyer, in which they ask her whether she had national security clearance at the time (she didn't) and asked her what she recalled of the police briefing and what she had told Mr Hall about that briefing.

Police also told Ms Hawthorne in that letter that "At this stage of the evaluation we have not established that there was any criminal conduct".

Assistant Commissioner Lammers has declined interview requests since, but at a media appearance on Thursday to announce a new police pursuit policy, he said the matter was still under investigation.

Asked whether the evaluation was looking at one staff member or went wider, he said, "Until the evaluation is complete, I'm unable to say how many people are being investigated, that's a matter for the investigating team."

Asked whether police were concerned simply about indiscretion on the part of staff, he said, "The purpose of the evaluation is to determine whether or not there was any criminality, that's the subject of the evaluation."

As to why police had told Ms Hawthorne in late January that no criminal conduct had been established, he said, "What we've said is, at this stage of the evaluation there's nothing to suggest to suggest that there was criminal conduct. But as I said, the evaluation is not yet complete."

The community should be satisfied police were doing a thorough job, he said.

Ms Hawthorne said on Thursday she had had no further contact with police. She has refused to answer the list of written questions from police.

Ms Burch was elected deputy speaker of the ACT Parliament on Thursday with the votes of her Labor colleagues and the Greens' Shane Rattenbury, despite objections from the Liberals. The Liberals say Ms Burch should not chair committees or preside in the debating chamber until the police have completed their investigation into her office, and Speaker Vicki Dunne even went so far as to consult other parliamentary speakers about her decision to block Ms Burch from the assistant speakers' panel.