Hardline Act list MP David Garrett is under fire for comparing homosexuality to paedophilia during the filming of a TVNZ discussion.

Garrett, a barrister and one of the prime movers behind his party's "three strikes" law and order policy, stunned panellists and production staff on TV One's Eye To Eye with behaviour described as "obnoxious" and "unbelievably unprofessional".

Sources said Garrett turned up drunk and offended production staff when the Willie Jackson-fronted show was recorded at TVNZ studios in June.

"He was so extreme, I couldn't believe it," said one. "He was in the green room and he was so drunk. "

Another said: "He disgraced himself. The show was a complete disaster".

Garrett would not confirm when he arrived at the studio but acknowledged he had had "a few drinks".

"I was at a business lunch that turned into a rather long one but I knocked off well before the show. It wasn't my finest hour. I don't believe I was offensive."

One studio staffer was so concerned about Garrett's condition she alerted executive producer Claudette Hauiti. After talking to Garrett, Hauiti decided to let him appear on the show.

During the show, Garrett, speaking slowly and occasionally slurring, made rambling comments which were rubbished by the other panellists, particularly former Act MP Deborah Coddington.

Garrett: "Paedophiles, like homosexuals, 30 years ago homosexuals had, according to experts, a disease and they needed to be cured and it was a spectacular failure because homosexuality is a sexual orientation, so we decided that because there were 10 per cent of people who were homosexual it was no longer a disease. Paedophiles cannot be cured any better than ..."

Coddington: "You can't bring homosexuality into it ... "

Jackson: "I don't understand this analogy."

Jackson later dismissed it as a "stupid analogy" and accused Garrett of having an "obsession" with homosexuals.

Hauiti said Eye To Eye regularly sought out controversial guests and Garrett was invited on as a legal adviser to the Sensible Sentencing Trust. "I did find him to be obnoxious. I told him we would never have him back again."

Coddington said she was shocked by Garrett's attitude: "He was really rude to me. He walked up and said `Deborah Coddington, my brother hates you'."

She said recording was stopped several times because of Garrett's behaviour but didn't think any more about the incident until Act announced Garrett as a list candidate.

"Then I saw a picture of him and I thought, `holy moly, it's him'. "I know Garrett's views are not Act views. [Leader] Rodney Hide and [deputy leader] Heather Roy wouldn't have those views."