Nikki Kaye is in a tight race to retain the Auckland Central electorate.
The prominent National Party MP is holding a slender lead over Labour's Helen Ione White, of just 247 votes with 21.5 per cent of votes counted.
Kaye, currently serving as Minister of Youth and Minister of Education, entered Parliament at the 2008 election, winning Auckland Central for the National Party for the first time in New Zealand's history.
She subsequently won the seat again in 2011 and 2014.
Kaye took four months' leave from her portfolios in September 2016 after she was diagnosed with breast cancer. She returned after treatment.
Helen White was put forward for Labour in the Auckland central electorate after Jacinda
Ardern left the area to campaign in the Mt Albert by-election.
White grew up in Freemans Bay, has three children and runs a local legal practice specialising in employment law.