New Zealand Prime Minister John Key voiced out on Friday his personal support for gay marriage, joining U.S. President Barack Obama who openly said yesterday that "same-sex couples should be able to get married."

In a statement, Mr Key stressed that "I am not personally opposed to gay marriage," but qualified that his personal stance on the issue does not necessarily reflect that of the New Zealand government.

"It is possible that parliament may consider a member's bill at some stage, but it is not on the government's agenda," Mr Key clarified, indicating that the country he governs is still a long-way in officially acknowledging gay unions.

Like Mr Obama, the New Zealand Prime Minister has been pressed by civil rights advocates to express his definite stand on the controversial debate despite the country already having laws that allow same-sex civil unions, which pretty much extend the same legal rights that previously were reserved to heterosexual couples.

Until today, Mr Key downplayed clamours for the NZ government to legally back the establishment of same-sex union in the country, insisting that the raging debate, which also exists in many countries around the world, was not the priority of his government.

Yet Mr Obama's landmark announcement on Thursday, which he described as the evolution of his personal stance on the issue following serious consultations with his family members and close friends, reignited the Australian Green Party into urging the federal government to reconsider its position on same-sex debate.

Greens Senator Sarah Hanson-Young said on Thursday that Prime Minister Julia Gillard should be inspired by Mr Obama's pronouncement of boldly going for marriage equality regardless of couples' sexual orientation.

"It's time for our political leaders to accept that the Australian people have it right on this one, and currently Julia Gillard and Tony Abbott are on the wrong side of history," Senator Hanson-Young told ABC yesterday as she lamented that both the Prime Minister and the Opposition leader were vehemently against the possibility of allowing gay unions in Australia.

"The majority of Australians support marriage equality, yet our Prime Minister doesn't," the Greens senator noted too.

Her colleague, former Greens leader Bob Brown, has expressed optimism that Mr Obama's change of heart on issue will "light the candle for those who are still back in the darkness of wanting this discrimination."

The U.S. President's gear-shift, Senator Brown added, should spur a policy revision for other global leaders "and help them to make the change as he's done."

But Mr Obama's redefined support for same-sex marriage and Mr Key joining in shortly proved not too much of an encouragement for Ms Gillard to rethink her stance on the matter.

"Obviously President Obama has and he's announced a decision ... (but) I've made my mind up and my position on this is well known," Ms Gillard said in an interview with ABC.

Ms Gillard stressed she remains firmly opposed to gay unions, pointing out that "this is a matter that people form their own views on, a deeply personal question, people will think about it, work their way through it."