It comes a day after he was named at a royal commission into police use of informers as the source of leaks about the woman now known as Lawyer X.

But Mr Pope on Wednesday insisted he did not tell Herald Sun journalist Anthony Dowsley, who broke the scandal, that Ms Gobbo was an informer.

"So you didn't tell Mr Dowsley that she was a human source," barrister Geoff Chettle, who is representing a number of police handlers in the inquiry, put to Mr Pope.

"No, I didn't," the former officer replied.

The commission is looking at how and why Ms Gobbo gave police dirt on her criminal clients during Melbourne's gangland war.

Mr Pope's denial about leaking Ms Gobbo's role as an informer comes a day after the inquiry was told about a note from homicide detective Sol Solomon in March 2014.

The detective claimed he had been told Mr Pope was the source of the leak.

According to the note, Mr Dowsley said Mr Pope disclosed the information when the journalist asked about Ms Gobbo's claims she had been in a sexual relationship with the high-ranking officer.

"Pope disclosed to (Dowsley) that F was a registered human source," Mr Solomon's note said, referring to Ms Gobbo.

She was known as Witness F in a police prosecution against former officer Paul Dale.

Those notes were then given to other senior police, including Inspector Boris Buick and assistant commissioners Steve Fontana and Mick Frewen.

Mr Pope was one of the first witnesses called in the commission and will be one of the last.

Hearings into Ms Gobbo's informing are set to wind up on Friday - day 127. A small number of public hearings will be held in April on policy-related issues.

Commissioner Margaret McMurdo is due to hand down her report on July 1.

Australian Associated Press