Mr Moore is in a Tasmanian Gay and Lesbian Rights Group advertisement that highlights the link between marriage and family.

The advertisements will be shown before the 15 upper house members vote on same-sex marriage legislation next month.

``If they can hope to change the minds of one or two of the legislative counsellors that would be great,'' Mr Moore said.

He said that those against marriage equality should ignore old prejudices.

Mr Moore's son Robbie, 30, told his family that he was gay seven years ago. ``Initially I was shocked but since, I've come to accept it,'' Mr Moore said.

``I found out my preconceptions were very much different from the realities.

``Once Robbie rang me and asked me whether I would do it, I asked him `did you want me to?' and he said `yes', and that is the end of the argument. You do what you can for your family.''

Robbie Moore who lives with partner Matt Hastings, 27, in Hobart, said that it was great to have his father's help.

``He has always been very supportive, certainly when I came out to him he found that challenging . . . it has been something that he has come to terms with as well,'' Mr Moore said.

``(But) he has been amazing. I am very proud and it was a good feeling to know that he is such a good supporter on this issue.''