Marriage equality laws have been introduced to the New South Wales Parliament, as the ACT fights to protect the same newly-enshrined right.

New South Wales Opposition frontbencher Penny Sharpe has introduced a bill to allow same-sex marriages in the state. Ms Sharpe is at the head of a cross-party group advocating the reforms.

“Equality before the law is not a privilege, not an indulgence, not a whim. It is a right,” Ms Sharpe told Parliament.

“This bill is for those who support equality for themselves and equality for others.

“This bill is for same-sex couples who want to be able to celebrate their love and commitment in the same way as friends and family.”

The group is confident of the legal grounds for its bill, as the ACT’s similar laws face criticism for not being strong enough to withstand Federal Government challenges.

“All of the best advice from people like Professor George Williams and barrister Brett Walker say that what we're doing is absolutely valid,” Ms Sharper says.

“There are two issues in NSW. Does the state has the ability to legislate for marriage? And the answer is yes.

“The second question; is what we're putting in inconsistent with the federal marriage law?”

“What the cross-party group hopes is that they will actually be able to see that it's perfectly legal and valid for them to be able to take this step.”

The ACT became the first Australian jurisdiction to allow same-sex marriage with the passing of its Bill last week. After being in place for a matter of hours, the Federal Government announced it was preparing its case to overturn it.

Experts and authorities had warned ACT officials to strengthen the wording of the legislation to enable it to survive the High Court challenge, with ACT Attorney-General Simon Corbell saying “the amendments proposed are about form rather than substance and do not add anything significant.”

The ACT matter will be back in the High Court on Monday.