Updated

The leader of a small New Zealand political party says he won't contest next month's election, making him the third leader to quit this month in a campaign that's been transformed by the rise of Opposition Leader Jacinda Ardern.

United Future leader Peter Dunne said Monday there's a mood for change in the district where he has served as a lawmaker for 33 years.

The move comes as a blow to Prime Minister Bill English and his conservative National Party, who relied on Dunne's support. Dunne was his party's sole representative in Parliament.

Three weeks ago, Opposition Leader Andrew Little quit following dismal polling, allowing Ardern to step into the position. A week later, Green Party co-leader Metiria Turei resigned.

Polls indicate a close election race between English and Ardern.