Green Party candidate Julie Anne Genter has conceded that Labour will probably win next month's Mt Albert by-election but says she will put her best forward.
Ms Genter will contest the seat vacated by Labour's David Shearer, who is headed for a United Nations job in South Sudan.
The by-election has been set for 25 February.
Senior Labour MP Jacinda Ardern will contest the seat for her party, while National will not field a candidate.
Ms Genter moved to New Zealand from her birthplace, America, in 2006, and has lived in or near the electorate for nearly 10 years.
She said Ms Ardern was likely to win but was excited to work alongside her.
"Having two positive, young women candidates who are both working to change the government is a real opportunity to get more people excited and interested in the positive potential of politics."
Her campaign would focus on issues around transport and housing.