Roy Farmer was the AFP's deputy commissioner of operations when his colleague Colin Stanley Winchester, the head of the ACT policing arm, was murdered in January 1989.

Eastman, who quickly became a suspect in the case, was targeted in a long-running surveillance campaign.

The suspect often complained about physical surveillance teams constantly tailing him and claimed he was being harassed.

Eastman's counsel, Mark Griffin, QC, questioned Mr Farmer in the Eastman inquiry on Tuesday about an alleged conversation he had with others at a function during a visit by Italian dignitaries at Parliament House.

Mr Griffin asked the former deputy commissioner whether he had told Cliff Foster, an AFP member attached to an office in Rome, the AFP's surveillance tactics were designed to drive Eastman ''nuts''.

Mr Farmer responded: ''I'm sorry, I've got to deny that. That's silly.''

Mr Farmer had previously written to the AFP's head of ACT region to urge for a reassessment of the surveillance tactics being employed by Richard Ninness, who led Operation Peat, the team investigating the Winchester murder.

He said Eastman had ''embarked on a campaign'' to publicly counter-attack the surveillance, including through The Canberra Times, by creating confrontational situations and then publicly voicing complaints of harassment. Mr Farmer wrote that meant it was time to think about changing the tactics.

In the inquiry on Tuesday, Mr Farmer asked why he would say to someone that the surveillance was designed to drive Eastman nuts, after earlier urging for a re-assessment of police tactics to avoid confrontation.

Earlier in his evidence, Mr Farmer said he became concerned when he learned that harassing phone calls were being made to Eastman's home from City Police Station. He said he had referred the matter to the appropriate area.