Julie Anne Genter has joined the race to become the Green Party's next female co-leader.

The American-born Minister for Women on Thursday morning announced her candidacy for the role that's been vacant since the resignation of Metiria Turei during last year's election campaign.

She is the second candidate to throw her hat in the ring, after Marama Davidson revealed she was running last week.

"I am putting my name forward to be co-leader because I believe I have the skills to articulate this vision and bring New Zealanders along with us," Ms Genter said in a statement.

"Under my co-leadership, it will be crystal clear to all that the Green Party is a force to be reckoned with, that will not be pushed around or taken for granted by anyone."

Ms Genter is also the associate Minister for Transport and Health and said those positions would let her raise the party's profile. She has been a member of parliament for six years.

Ms Davidson is of Ngapuhi descent and entered parliament in 2015 after spending 10 years at the Human Rights Commission.

The Greens are set to elect their new female co-leader on April 8 to fill the position vacated by Ms Turei, who resigned amid a benefit fraud scandal.

The party's constitution mandates there must be a male and female co-leader.

Nominations opened on February 2 and will close on Friday. Senior MP and conservation minister Eugenie Sage and Jan Logie have also been tipped as possible candidates.