Labor MP John Quigley has told the State Administrative Tribunal he will fight a charge of bringing the legal profession into disrepute.

The Legal Practitioners Complaints Committee has brought the charge against Mr Quigley for threatening to reveal the identity of an undercover police officer in 2002.

Mr Quigley phoned the officer and told him he would name him in parliament unless he agreed to tell the truth about his involvement with the Andrew Mallard case.

Mr Mallard spent 12 years in jail for the 1994 murder of Mosman Park jeweller Pamela Lawrence, before his conviction was overturned in 2006.

Mr Quigley denies he threatened the undercover officer and says he merely encouraged him to come clean.

"I'm not guilty, I'm going to stand my ground," he said.

"All I ever sought to do was expose the corrupt practices that led to and at the time was still keeping Andrew Mallard corruptly imprisoned."

Mr Quigley said earlier that he did not regret his actions.

"Playing a role in securing the acquittal of an innocent man who had at that stage been held in custody for some 12 years, you can't then hesitate because you know you might get a backwash," he said.

He says the incident has already been reviewed by the Corruption and Crime Commission.

"At the conclusion of which the Commissioner said well look whilst it's generally undesirable to say these sort of things this is an exceptional circumstance and it led to Mr Mallard's appeal getting up and he's to be commended for it," he said.

The hearing has been adjourned until July.