"When it comes to the Marriage Act, that is the responsibility of the Federal Parliament," Mr Rudd said. "And the Marriage Act relates to a union between a man and a woman, and that remains Labor policy as it has been into the past and as it will remain into the future."
Australian Coalition for Equality spokesperson Rodney Croome said the community was disappointed by Mr Rudd's comments.
Mr Croome said that partners in same-sex relationships would continue to be second-class citizens while they were denied the right to marry.
"It's disappointing that Kevin Rudd is not willing to reconsider this issue given that the most recent polling shows almost 60 per cent of Australians support same-sex marriage," Mr Croome said.
On gay adoption, Mr Rudd said such laws were governed by the states.
Journalists asked fruitlessly for Mr Rudd to state his personal view of gay couples adopting children. "As I said, these things are regulated by the states," he responded.
Asked repeatedly to declare his personal opinion, Mr Rudd refused.
"That is my view, and that's how I have responded," he said.
Mr Croome said Mr Rudd insisted that he would love one of his children equally if they came out as gay.
"So why can't he treat that child's love for their same-sex partner equally too?" he said.
Mr Croome said it was annoying that Mr Rudd could not provide any solid rationale for his party's position beyond "tradition" and what he said were some very misleading claims about practical problems in areas such as inheritance and social security.
"It was traditional for interracial marriages to be banned, but that didn't make it right," he said.
Mr Croome said there were no practical problems recognising the inheritance rights of same-sex partners in all eight states and territories.
He said Labor's policies on same-sex entitlements had improved significantly since the last federal election with a commitment to legalise equality for de facto same-sex couples and to having relationships registries in each state.
"Labor's current policy will address some of the deep disadvantage and discrimination which currently exists in Australian law," Mr Croome said.
"But even if Labor fulfils all of its promises it will still not be possible for same-sex partners to publicly and officially declare their love for each other in front of their family and friends, as they can in many other Western countries," he said.
"Labor is effectively saying same-sex couples can get on the bus, but we still have to sit at the back."