The detective who arrested former NT police chief John McRoberts' lover Xana Kamitsis has described a heated meeting in which the commissioner told senior officers he had no conflict of interest.
Kamitsis, a married travel agent and former chair of Crime Stoppers NT, who had an affair with McRoberts, was one of a number of agents jailed for rorting a taxpayer-funded concession scheme aimed at helping pensioners see family.
At a meeting of senior police in 2014, an "irritated, irate" McRoberts walked around the room while everyone else was seated, former senior detective Clinton Sims says.
"He said he had a social relationship with Ms Kamitsis, he knew her but he was not in conflict," he told the NT Supreme Court on Thursday.
He was speaking at the trial of McRoberts, who is charged with attempting to pervert the course of justice by deflecting the fraud investigation into Kamitsis and the other travel agents.
He could be jailed if found guilty by a jury, with the four-week trial nearing its end.
McRoberts also told senior detectives in charge of the fraud investigation that they lacked the evidence to pursue any of the travel agents.
"Those meetings were more a case of being spoken to as opposed to a conversation and he was dismayed by the lack of information at hand," Mr Sims said.
He also asked why Kamitsis' travel agency had been selected as the "pilot case" to be pursued first, and was told it was because the value of her transactions were substantially higher, meaning she was the greediest.
Mr Sims told the court the investigation stalled with McRoberts allegedly blocking a search warrant, personally reviewing his investigation files and imposing his preference for the recovery of government money via civil and not criminal means, all highly unusual for a police commissioner.
"It was certainly peculiar, something I have never seen in my time in the police force with this exception," he said.
McRoberts denies any wrongdoing.
His lawyer Tony Elliot suggested to Mr Sims that his memory of the meetings from four years ago were false and were not written in his diary at the time.
Mr Sims said he had made a statement to federal police in 2015 about McRoberts' conduct in that meeting.