Gay couples to dine with PM

Same-sex couples hope dinner party talk will help change Prime Minister Julia Gillard's mind about gay marriage.

On Tuesday Prime Minister will dine with couples in same-sex relationships at The Lodge in Canberra.

The dinner was won by GetUp and Australian Marriage Equality in a charity auction in June.

There are three gay marriage private members bills before federal parliament.

At the ALP national conference in December Labor decided government MPs could have a conscience vote on the issue.

However, Ms Gillard has said she opposes gay marriage.

Brisbane lesbian Sharon Dane and her wife Elaine Crump will be among the attendees.

They've been together for 10 years and got married in Canada in 2008.

"We came back to have our marriage not recognised in our own country," Dr Dane told AAP.

She said same sex couples favour marriage over civil unions.

Dr Dane said Ms Gillard's opposition to gay marriage was "conflicting."

"Same sex couples should be able to make the choice for themselves," she said.

She is confident Australia will legalise gay marriage in coming years, even if it takes a conservative government to do it.

"The whole world is moving in that direction," Dr Dane said, adding it was a matter of when, not if.

"Australia will have to follow suit. It's embarrassing if nothing else."

Australian Marriage Equality spokesman Alex Greenwich will also attend the dinner.

"We will share with prime minister why celebrating the meaning of marriage is so important to all Australians, including gay Australians," he said.

"We also hope to use the dinner to alleviate any concerns that the prime minister may have around the issues of religious freedoms and protections."