Labour's Hauraki-Waikato MP Nanaia Mahuta will contest the Labour Leadership.
Ms Mahuta said late this afternoon she had made the decision to stand after giving the matter serious consideration.
"This decision has been made with the knowledge that if the party reviews the election outcome, we can learn from the base of support that was demonstrated across Maori electorates in South Auckland and amongst Pacific and ethnic communities."
Ms Mahuta's announcement brings the number of contenders to replace David Cunliffe to four with former Deputy leader David Parker, Andrew Little and Grant Robertson also in the running.
Her candidacy announcement at 4.30pm came just before the deadline of 5pm.