Minutes later she was in the nursery unit and her partner, who had just had an emergency caesarean section, was nowhere to be seen.

"They just kept saying "she's coming, she's coming," that was it," she said.

"I didn't get any medical information whatsoever."

Rebecca found out four hours later that her partner's blood and heart pressure had dramatically increased.

The staff didn't tell her "things were getting really intense."

She said her partner, upon visiting the antenatal clinic, listed her mum as next-of-kin because Rebecca was not "classified as family." It would have been a completely different story if they had been married.

"They would've told me exactly what was going on, where she was and why it was taking so long," she said.

"We would've been treated as family, not just her baby and the friend that's there."

The difficulties continued when they applied two weeks later for a birth certificate at NSW Births Deaths and Marriages. It took four months to receive the certificate and for her to be given her legal rights as a mother.

"We needed to prove that we lived together, we needed to show that we had things at the same address and we we're actually a couple," she said.

"It takes away your experience of being a new parent, it really does."

With the passage of same-sex marriage through Parliament last week, married same-sex couples will be able to be recognised automatically as next-of-kin for the first time.

"Previously, it was all too easy for officials to ignore or misunderstand the law and deny same-sex partners recognition as next of kin or beneficiaries, and de facto couples needed to 'prove' their relationship through evidence such as mortgage or utility bills, rather than being able to simply point to a wedding ring or marriage certificate," said the director of legal advocacy at the Human Rights Law Centre, Anna Brown.

"Even couples in registered relationships or civil unions couldn't be certain their relationship would be recognised if they stepped over the border from NSW to Queensland, for example."

Ms Brown said that although couples have the same substantive legal rights as de facto heterosexual couples, their relationships are now equal under federal law which eliminates past practical difficulties.

"With marriage comes access to immediate legal recognition and this removes a big source of stress and uncertainty for same-sex couples," she said.

Professor Paula Gerber from Monash University Law Facility said that same-sex couples can now also use their marriage certificate to be recognised as their partner's beneficiary.

She said this was difficult in the past in circumstances where individuals didn't document exactly what they wanted to happen to their estate in their will.

"When it comes to what happens to your estate when you die, it goes to your partner and children under the laws of intestacy. For same-sex couples that couldn't get married that wasn't necessarily going to be the outcome," Professor Gerber said.

She advises newly-wedded couples to make a will after their marriage and to seek legal assistance to "make sure you get it right."

"Marriage voids the will, so if they don't create a new one then the laws of intestacy would govern," Professor Gerber said.

Two years on from the birth of their first child, Rebecca is looking forward to getting married after it becomes possible to do so on January 9. More kids are also on the cards.

"We're pretty sure our next experience will be totally different because we're equal now," she said.

"I guess I'll be treated like the partner, not like the friend."

*Rebecca's last name was withheld at her request.