Green MP Gareth Hughes has confirmed he will enter the contest to replace Russel Norman as male co-leader.
Mr Hughes is the second MP to put his hand up for the role after Kevin Hague.
In a statement, Mr Hughes said he believed he could do the best job to grow the Greens' vote. "I am now in my third term of Parliament and ready to lead," he said.
The Wellington-based MP is ranked fifth on Greens' list and speaks for the party on energy, mining, and ICT.
At 33 years of age he is one of the youngest MPs in Parliament.