Commissioner Reece Kershaw has faced questions about his relationship with former NSW Police commissioner Mick Fuller, now a partner at PwC.
The consultancy firm's former head of international tax, Peter Collins, is alleged to have improperly used confidential Commonwealth information, with the matter being investigated by the AFP.
In May, Mr Kershaw told Senate estimates he was contacted by Mr Fuller over the unfolding tax scandal.
A spill-over estimates hearing is investigating the matter further and in his opening statement, Mr Kershaw said he and Mr Fuller had a "collegial relationship" but the pair did not socialise.
"Mr Fuller and I do not have dinner at each other's homes, we do not play golf together and I don't know the personal details of his life," he said on Friday.
"The majority of the conversations Mr Fuller and I have had are about matters relating to our former or current roles or policing issues in general.
"What we have in common is dedication to service to the community and keeping our people safe."
The commissioner also addressed a $794,000 contract PwC was awarded to review ACT Policing, led by Mr Fuller.
Mr Kershaw was not involved in the procurement process but said Mr Fuller was selected because he was "the best person for the job".
"The contract Mr Fuller undertook was a job for a former police commissioner who had the required knowledge and expertise for a review," he said.
"It was critical the reviewer had a contemporary skill set and knowledge of the unique operating environment of the ACT."
AFP chief operating officer Charlotte Tressler previously worked in various roles at PwC, including as a director, for just over 13 years.
Ms Tressler had not previously disclosed her previous employment to the committee but said it was openly listed on her LinkedIn profile.
"I have actively declared any potential conflict of interest for any procurement that I have been actively involved in," she said.
"I have in no way attempted to hide my previous employment relationship with PwC."
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