Peter McEwan was just 17 when the police caught him caressing another man behind some bushes on Brighton beach in 1967.

It was enough for him to receive a criminal conviction while he was still finishing year 12.

He said police had written a confession for him and he agreed to sign it.

"I was an innocent boy. I trusted the police," he said.

Later his story was splashed on the front page of The Truth newspaper.

In parliament on Tuesday Premier Daniel Andrews apologised to Mr McEwan and other men who were convicted under homophobic laws that have now been scrapped.

"There was a time in our history when we turned thousands of ordinary young men into criminals," Mr Andrews said. "And it was profoundly and unimaginably wrong."

He apologised for the laws the parliament had passed and the "lives ruined".

"It all started here. It will end here, too."

Mr Andrews raised the individual cases of several men affected by the laws. He said he also learnt of two women convicted for offensive behaviour in the 1970s for holding hands on a tram.

Opposition leader Matthew Guy also apologised. He told parliament the apology was long overdue.

"It's about time and it is right," My Guy said.

Mr McEwan sat in parliament's public gallery with some of his siblings to hear the apology. Other men who received criminal convictions or were charged with offences were also present alongside their supporters.

They sat quietly, some nodding gently or occasionally rubbing their eyes.

Police Chief Commissioner Graham Ashton was present and posed in photographs with the men on the steps of parliament before the apology.

Human Rights Law Centre director of advocacy Anna Brown said there were young gay and lesbian people around Australia struggling with their sexuality.

"This apology will help ease the shame and stigma felt by these young people who are finding their place in the world," she said.

Justice Connect manager of project development Alan Yang said he hoped the official apology would raise awareness and encourage people affected by the former laws to apply to have their records wiped clean.

"This is our one and only chance to get this in the public eye," he said.

Mr Yang said free and confidential legal advice was available through the Human Rights Law Centre for people wanting their records expunged.

He said the bigoted laws claimed many victims. In one case, 14-year-old Tom Anderson was forced to perform sexual acts on his employer but when he reported the abuse to police they charged him with buggery.

Although no conviction was recorded against him the experience was highly traumatic and had a major impact on his life.

The former Coalition government, under then premier Denis Napthine, introduced laws to expunge the criminal records of men convicted of gay sex before homosexuality was decriminalised in Victoria in the 1980s.