An openly gay MP in New South Wales (NSW), Australia, has said that she is not convinced that an equal marriage bill would currently be able to pass in the state’s parliament.

Responding to the news that neighbouring country New Zealand had passed the equal marriage bill, and saying she was very happy that it had, Labor MP Helen Westwood, said there had been support for equal marriage in the lower house of the NSW Parliament.

She went on to say that it was encouraging that MPs in New Zealand once opposed to equal marriage, had come out in support of it once they spoke to constituents.

“I’m not convinced that such a motion would actually pass in the upper house, it may be defeated at the moment,” Ms Westwood said in an interview on Thursday.

Independent Sydney MP Alex Greenwich had a different stance on the issue. He said that New Zealand’s vote showed the campaign for marriage equality was an “unstoppable force”.

“The growing international pressure that was just taken up a notch with New Zealand embracing this important reform is sending a message that marriage equality is unstoppable,” he said.

“If New Zealand can do it Australia can as well.”

New Zealand became the first country in the Asia-Pacific to legalise equal marriage, as well as the third of the 54 Commonwealth member states, and the second of Queen Elizabeth II’s realms, as its parliament voted on Wednesday for the bill 77 to 44.

As the Parliament of New Zealand passed a bill to allow equal marriage in the country, those in attendance of the reading broke into song, once it was announced that it had passed.

Gay rights campaigners in Australia have praised New Zealand after the vote. Despite the celebration, Australia’s Prime Minister, Julia Gillard, said she would not be dropping her opposition to marriage equality.

Along with Gillard, Australia’s opposition leader Tony Abbott continues to oppose equal marriage and refuses to allow his MPs a conscience vote.

Efforts to legalise the measure failed in the Australian Parliament last year.

According to a survey by an equal marriage advocacy group, over a thousand Australian gay and lesbian couples are to travel to New Zealand in order to get married, which could boost the New Zealand economy by around £472 million, they estimated.