Paul Mullett and Noel Ashby had a 'toxic' relationship, court told

PROSECUTORS have described the relationship between Noel Ashby and former police union boss Paul Mullett as a "toxic one".

PROSECUTORS have described the relationship between former assistant police commissioner Noel Ashby and former police union boss Paul Mullett as a "toxic one".

The Melbourne Magistrates Court heard the two men exchanged information and favours for their own advantage during the committal hearing for charges of perjury against Mr Mullett.

The former police association boss is fighting five charges of perjury, attempting to pervert the course of justice and breaching the police regulations act.

Prosecutors allege Mr Ashby passed information about the confidential investigation into the murder of gigolo Shane Chartres-Abbott, codenamed Briars, on to Mr Mullett.

They argue Mr Mullett then warned the serving police officer who was under suspicion of involvement in the murder - via another person - that his phone was bugged and to be careful what he said.

The investigation came after a criminal told police he was the gunman in the 2003 murder of Chartres-Abbott and he had been assisted by a serving and former police officer.

"It's a long standing relationship between Mr Ashby and Mr Mullett and it’s a toxic one,'' prosecutor Chris Ryan said.

"These men are trading information...for their mutual benefit and trading favours for their mutual benefit.''

The committal hearing continues.