Mr Mullett took the stand in the Supreme Court on Wednesday as part of his lawsuit against former Victoria Police chief commissioner Christine Nixon, alleging he was the victim of a "malicious prosecution" that cost him his career.

The court heard about the escalating disputes between the union and Victoria Police that led up to Mr Mullett's suspension from the force in November 2007 after he gave evidence at an Office of Police Integrity hearing.

Those conflicts centred on the negotiation of an Enterprise Bargaining Agreement in 2006 and 2007, the court heard, as well as the involvement of Victoria Police in a Police Association bullying allegation.

The Police Association repeatedly expressed concern to its members that police powers from the Ethical Standards Division would be used to investigate what was considered an internal matter, the court heard.

Mr Mullett gave evidence that he believed Victoria Police had put him under surveillance as early as December 2006 as part of the wider plot to have him removed.

He told the court neighbours at the union's East Melbourne offices had seen people rifling through rubbish for documents, which he said was a "well-known investigative technique".

The court also heard that Mr Mullett had witnessed a fellow member of the Police Association executive place or remove a listening device from a boardroom table.

When Mr Mullett approached Assistant Commissioner Luke Cornelius from the Victoria Police Ethical Standards Division about being watched, he said he was told there was no surveillance on him.

"Did you accept that statement?," asked plaintiff barrister Andrew Panna QC.

"Not totally," responded Mr Mullett.

Mr Mullett's counsel also tendered a series of police union newsletters in court as evidence of the growing animosity between Ms Nixon and Mr Mullett.

In one newsletter circulated to members, Ms Nixon was condemned for becoming involved in the bullying allegation because it was causing anxiety and low morale among staff.

Mr Mullett told the court the notice was published after a resolution by the nation's police unions, who were concerned that Ms Nixon's "interfering" behaviour could cause a "spillover effect" into other states.

Ms Nixon smiled and laughed quietly when Mr Mullett's barrister produced a transcript of an interview with ABC Radio National in 2003, which was quoted in the police union newsletter.

"I...did Industrial Relations because I wanted to learn the rules to fight the union because I figured I should hold them accountable to what I understood to be the industrial rules," she was quoted as saying.

When asked about his appearance at the OPI hearings in November 2007 which resulted in his suspension, Mr Mullett said he was not told at the time why he was being summonsed.

Ms Nixon suspended Mr Mullett on the belief his evidence at the hearing implicated him in the leaking of information about a murder investigation.

Mr Mullett was charged in July 2008 with perjury, perverting the course of justice and wilfully making a false statement. Those charges were later dropped due to a lack of evidence.

When asked why he didn't appeal his suspension at the time, Mr Mullett told the court he did not think he would get a fair hearing.

Ms Nixon denies orchestrating any plot to remove Mr Mullett as union secretary.

The trial continues.