The Northcote by-election will be on Saturday 9 June, Prime Minister Jacinda Ardern has announced.

The byelection was triggered by the resignation of Jonathan Coleman who is leaving to take up work with a health insurance company.

National has already drawn up its shortlist of potential candidates: Dan Bidois, Danielle Grant, Darren Ward, Lisa Whyte and Simon Watts. Under its rules they cannot speak to media until after the selection. Bidois is a Harvard-educated economist who works for Foodstuffs and unsuccessfully sought the selection for Pakuranga last year.

Simon Wilson: Northcote notebook - why this byelection matters


Ardern has also indicated spending in the Budget will focus on the public services - in particular health and education. She said news in recent weeks had shown the dangers of letting funding in those areas slips. She said since coming into Government and opening the books Labour had found a significant shortfall in those areas.

She said the case of Middlemore Hospital buildings "rotting around the patients" showed the urgency of the work needed.