Mr Watts said some members of his family, who were conservative and religious, struggled to accept his uncle when he came out as gay in the Joh Bjelke-Petersen era.

"So I am tossing the script and talking about a gay man that I knew: a man that I called my Uncle Derek but who my Uncle Ian was never able to call his husband."

"Reading Senator Abetz's comments made me wonder whether he had ever met a gay man before," he said in a speech to Parliament on Wednesday .

Victorian Labor MP Tim Watts, who is regarded as one of the party's rising stars, said he abandoned plans to give a more routine, impersonal speech in support of same-sex marriage after reading Senator Abetz's comments.

"It's a horrific thing to watch someone die from AIDS," he said. "It was particularly horrific in the Queensland of the 1980s and '90s - to have to do so not only with the horrors of the illness but the indignities and horrors of a lack of recognition from the society around you. To have to deal with being beaten by hateful thugs on the street while your body was destroying itself from the inside."

Leader of the government in the Senate, senator Eric Abetz. Credit:Alex Ellinghausen

Mr Watts said his uncle was great with children and would have made a great father.

"I know that in light of the last 24 hours he would have wanted me to deliver a political message in the chamber here today. He would have wanted me to say to Senator Abetz, 'Do not claim to understand what gay Australians want, do not tell them what they do or don't want. Do not use the law to deny them the equal right to choose the sam recognition for their relationships as heterosexual couples.'"

Mr Watts said most Australians regard senator Abetz and Prime Minister Tony Abbott as "anachronistic jokes" for their opposition to same-sex marriage.