Sue Bradford and Matt McCarten have rejected speculation they are about to start a new left-wing party - but neither will rule out doing so at some future point.
The Labour-leaning Standard blog yesterday reported rumours that Ms Bradford, Mr McCarten and Maori Party MP Hone Harawira would begin a new left-wing party during the Mana byelection campaign.
Yesterday, both Ms Bradford and Mr McCarten said there were no current moves to do so and they had not discussed the idea with each other.
However, both believed there were virtues in the idea.
Ms Bradford, who resigned as a Green Party MP last year, said that although she had no plans to found a new party at the moment, "I'm not saying I never would".
Mr McCarten said it was possible speculation about a new party arose because Ms Bradford was speaking at a Unite conference a week after the byelection.
He said he had always believed it was important to have a strong progressive party outside the Labour Party because it could push Labour to move on issues such as employment rights. He believed the Alliance was effective at this when it was in its heyday. "So it's something I've always said I believe in, but it's not something you just invent."
Mr McCarten, a former Alliance president, is standing in the Mana by-election with the backing of his Unite union and campaigning on workers' rights such as a $15 minimum wage.
Ms Bradford has set up an "alternative welfare working group" in response to the government-appointed group considering welfare reform to object to National's changes to employment laws.