Former Green MP Sue Bradford will stand for the Mana Party in Waitakere - but will seek the party vote only to increase Labour's chances of taking the seat back from National's Paula Bennett.
Ms Bradford was formally selected by Mana to stand in the seat yesterday.
She said there was a risk she would split the vote on the left, but she intended to make it clear she only wanted the party vote for Mana in the electorate.
Ms Bennett won the seat from Labour's Lynne Pillay by a slim margin of 632 in 2008.
Labour's 2011 candidate, Carmel Sepuloni, said she was not overly concerned Ms Bradford's high profile would create a significant split of the vote on the left, damaging her own chances of winning.
"She made it very clear she's going for the party vote only. So we will see her out on the campaign."
She said the Green Party candidate had also publicly endorsed her, telling people at a community meeting to give their electorate vote to Ms Sepuloni. The Green Party candidate got 1676 votes last election - more than Ms Bennett's winning margin.
Ms Bradford said Mana's strategy was to campaign for the party vote in the general seats but to run "two ticks" campaigns for both the electorate and party votes in the Maori seats. Mana leader Hone Harawira's Te Tai Tokerau seat could be a lifeline for the party if it does not reach 5 per cent.
This week broadcaster Willie Jackson said he would not stand in the Tamaki Makaurau seat because he did not want to split the vote and hand the seat back to Labour. Labour's candidate Shane Jones will contest the seat against Maori Party co-leader Pita Sharples. Hone Harawira's sister-in-law Stephanie Harawira will seek the selection instead.
Mana is also likely to select Annette Sykes to stand against Maori Party MP Te Ururoa Flavell in Waiariki and former Maori Party candidate Angeline Greensill in Hauraki-Waikato, held by Labour's Nanaia Mahuta. No announcement has been made on which electorate John Minto might stand in.
Ms Bradford will also be Mana's spokesperson on housing and social wellbeing, including welfare, children, family and the community sector.
Ms Bradford left the Green Party after Metiria Turei was elected co-leader over her. At the time, she expressed concern that the party was putting less emphasis on social issues - an area close to her heart.
Maori Party's Te Tai Tokerau candidate Waihoroi Shortland said Ms Bradford was trying to get a "free ride to Parliament on the backs of [Te Tai Tokerau] people".
"The question is why would Te Tai Tokerau carry someone who couldn't stomach the thought of being second-best to a Maori woman in the Green Party and in a tiff caught the next train out of town. Now she wants Maori to clip her ticket for the return trip."
When told of the comment Ms Bradford said she was "reluctant to respond to such an underhanded and ill-founded attack".