CONTENDER: Maori Affairs spokesman Shane Jones has the charisma but has blotted his copy book with some past deeds.

CONTENDER: Justice spokesman Andrew Little has the gold standard left-wing credentials, but will he appeal to enough voters?

CONTENDER: Foreign Affairs and Trade spokesman Phil Goff has supposedly ruled himself out, but will he have another tilt?

CONTENDER: Finance spokesperson David Parker has ruled himself out, but is considered a solid pair of hands.

CONTENDER: Revenue spokesman David Cunliffe is not as popular in the caucus as he is outside.

CONTENDER: Deputy leader Grant Robertson is smart and a hard worker, but do the wider public know him?

Georgina Beyer, the world's first transsexual mayor and MP, warns New Zealand is not ready for a gay prime minister and may be seeing a social conservative backlash.

With the Labour leadership up for grabs, it raises the question of whether Grant Robertson, the gay deputy leader, could be elevated to head the party, making him a strong possibility for prime minister.

But Beyer, who was an MP for eight years until 2007, said Labour needed to be realistic.

"I don't think we're ready yet," Beyer said. "It's not because Grant isn't capable, I think he's very capable . . . but the stigma that rests over those of us who are out, proud and gay who get into public office becomes untenable because you never shake it off and you get pigeon-holed."

Beyer said it was possible the debate over gay marriage, which became legal this month, had invigorated social conservatives, meaning New Zealand was less ready for a gay prime minister now than it was a year ago.

"I get the feeling out there that there's a little bit of a backlash to what is being labelled social engineering that is being constructed, and I just fear that Grant would be laboured with a lot of that baggage."

However, gay media personality Steven Oates said the marriage debate proved just the opposite - that we are ready.

"The Marriage Equality Bill has restored my faith in New Zealand as a whole," Oates said. "I think we are bigger than that now."

TV presenter Alison Mau also believes New Zealanders' attitudes had changed sufficiently to allow an openly gay man or woman to lead the country.

"I do think New Zealand has come far enough, yes," said Mau, who is in a same-sex relationship.

She says the passing of the Marriage Amendment Act illustrated Kiwis' social beliefs had evolved to a point where a person's sexuality would not affect popularity as a political leader.

"New Zealanders have shown how open minded and progressive we are," Mau said.

She refused to believe that who Kiwis voted for would be affected by sexuality.

"I would hate to think that New Zealand voters would turn against somebody that was a proven and capable leader just because of his sexual preference. That would be a tragedy. [But] I think it would a great thing to have a gay prime minister," she said.

Left-wing political commentator Chris Trotter believed Robertson's sexuality wasn't an issue.

"Grant's gayness is like Barack Obama's blackness. People tend to see right through it," Trotter said, adding that Robertson was articulate and intelligent and "makes you focus on what he's saying".

While Trotter accepted there were always "bigots" who would "not react well" to a gay leader, there were other factors which may drive their vote.

"There may have been a whole lot of sexists out there who didn't care much for Helen Clark, but who were very happy to have a Labour Government."

John Tamihere, a former Labour MP turned radio presenter, said New Zealand could, in theory, accept a gay prime minister, but it would have to be someone whose sexuality was not core to their reason for entering politics.

The problem for Robertson, Tamihere said, was that the Labour Party was associated with a string of pieces of legislation which amounted to "extraordinary activism".

This ranged from reform of matrimonial property legislation to cover same-sex relationships, the introduction of civil unions and gay marriage, which Tamihere said was effectively Labour legislation.

"Because of the contemporaneous nature of where Labour has taken gay rights, it's very hard to distance a Grant Robertson from the authority that the rainbow division has within the party."

Trotter and Tamihere said David Cunliffe should be the new Labour leader while Beyer said she was "leaning towards" Cunliffe.

Should Robertson be elected leader of the Labour Party, his homosexuality could even lead to a groundswell of support, Mau believes.

However, given current polling Mau suspects whoever is chosen Labour leader would face an uphill battle to dethrone John Key.

"Were [Robertson] to become leader we may have a few years to get used to the idea," she said.

GREENS EASY WITH LABOUR

A generation of politicians who have worked only under the MMP system means that whoever becomes the new Labour leader will be an easy coalition partner for the Green Party, says former Green leader Jeanette Fitzsimons.

The Greens have refused to say who their preferred candidate in the Labour leadership contest is, but Fitzsimons said she expected the party would find all three likely contenders - David Cunliffe, Grant Robertson and Andrew Little - easy to work with.

"The Greens are both in collaboration with Labour, and in competition, and there is an awful lot where we don't agree - but the only way forward for the country is for us to work together," Fitzsimons said.

"And . . . I would imagine the Greens would work with any of the current contenders for the leadership.

"Government these days is about negotiations, and if it's someone you can trust you are already a long way down the track to a good government - coalition governments are based on trust and I think all the current contenders understand that.

"None of them have been in parliament since the old first-past-the-post days and so they do have a different perspective and different expectations, as do the public, about how parties will co-operate."

Fitzsimons said she had worked before with both Robertson and Cunliffe and "got on fine . . . they are both good to work with and understand goodwill and that's a good start".

She had no personal dealings with Little, but had no reason to believe he would be any different. "I think the Greens will be quite pragmatic and try and form a good working relationship with whoever wins."

Former Green MP turned Mana Party activist Sue Bradford, who said she had always liked Cunliffe, said he might be more closely aligned with Green policy but that could prove bad for their vote because he could reclaim some of the disaffected Labour left, especially in Auckland.

"The Greens benefited a lot from Labour's very parlous state; they have built their own constituency but I think part of it came from defeated Labour voters and if Labour got more vibrancy back that would be threatened."

Former Green MP Keith Locke said it was too early in the contest to say which of the trio would prove best for the Greens.

"I'd be interested to see as the leadership contests proceeds to hopefully get a better picture," Locke said. "Both Cunliffe and Robertson are fairly good presenters, so it becomes a question of the policies they espouse.

"It's a bit unclear at the moment what policy differences there are between them, and presumably as they go around talking to the party a clearer picture will emerge."

Both Fitzsimons and Locke seemed sad to see former leader David Shearer depart.

Fitzsimons said it was "a shame that being a good and principled and honest and caring person is not enough to be prime minister because I think David Shearer was all of those things . . . I think it's sad that in politics, really good people often don't make it".

She said that Shearer's approach to international policy had been good but she didn't feel he "went far enough" on issues of climate change and sustainability.

Locke, meanwhile, said Labour took some "good stands" under Shearer and praised his "reasonably strong position" on opposing the GCSB bill compared to the record of the Clark Labour government on intelligence issues.

Green co-leader Russel Norman wouldn't discuss the candidates. "It's Labour's business," he said.