The Federal Government has announced it will give same-sex Australian couples who want to marry overseas a certificate of no impediment.

The certificate, which is required by some countries for heterosexual and same-sex couples, proves a person is over 18, is not married, and that there is no other barrier to them getting married.

Until now the Government only provided the certificate for heterosexual couples but same sex couples will be able to apply for the document from February 1.

Attorney-General Nicola Roxon says while it does not mean a same-sex marriage is recognised in Australia, it does remove a discriminatory hurdle.

"Same-sex couples have been very insulted that they can't get from their government a certificate which says they're not married to anyone else," she said.

"We are not by this step, recognising in any official way the marriage. What we're doing is providing a certificate in the same way we do for heterosexual couples to say that there's no legal reason that provides another impediment to people being married.

"It's a pretty basic thing and that prevents them from benefiting from the laws of another country. So it's a removal of discrimination rather than the next step, which our Australian Parliament hasn't yet dealt with."