National's Scott Simpson has kept the Coromandel seat blue, but Labour's calling it "purple".
The electorate includes Thames, Whitianga and Whangamatā, but extends through Waihī Beach, Katikati and Matakana Island, to Whakamārama just north of Tauranga.
National's Scott Simpson has held the seat since 2011 and this year's preliminary results give him the seat with 19,241 votes of 41,180 cast.
But his winning margin dropped steeply from 14,326 in 2017 to 4,206 in 2020.
The National Party got most (51.2 per cent) of the party votes in Coromandel in 2017 but this year Labour won the most with 42.7 per cent, while National took 33.7 per cent.
Simpson told the Bay of Plenty Times Labour's gains in Coromandel reflected the "electoral tide" this year but his seat stood up "particularly well".
He was "extremely humbled" to retain it, describing it as "a privilege".
For the wider party "it was a tough campaign and a tough night" he said, getting results.
Simpson joined supporters and volunteers at Richmond Villas in Thames for election night.
When asked how confident he was going into the evening, Simpson told the Bay of Plenty Times he "never takes anything for granted" and had "worked hard" throughout the campaign.
"I have been a National Party member since I was a teen and my goal has always been to serve the party as best as I can."
He moved away from his traditional approach of door-knocking and holding large public meetings in 2020, due to Covid-19.
"It has been a very long, drawn-out period," he said.
Labour's Nathaniel Blomfield described Labour's increased support in Coromandel as "a huge win".
He said reducing Simpson's margin by 10,000 votes, from 2017, put the seat "in striking distance" and it was now "more purple than blue".
"We have just got to keep up the momentum."
At 76 on the Labour list, he won't be brought in as a list MP.
Supporters and volunteers gathered with Blomfield at the Labour rooms in Thames, for the evening.
Looking back on the campaign Blomfield said: "It was definitely very stop-and-start, stop and start, which made it arduous."
"But there was a lot of positivity from people, particularly around the large government responses [in the last three years]."
Contesting the electorate alongside Simpson and Blomfield were several newcomers.
They included Green Party candidate Pamela Grealey, Act Party candidate David Olsen, Rob Hunter for The Opportunities Party, Advance NZ's Tony Brljevich, New Conservative's Michael Egleton, Steven Hart for NZ Outdoors Party and Bob Wessex for Not a Party.
In the 2018 Census, Coromandel had the highest proportion of people aged 60-64 years (8.2 per cent), those aged 65-69 (9.2 per cent), and those aged 70-74 (8 per cent) of any electorate.
More than one-third (35.3 per cent) of private dwellings were unoccupied, also the highest proportion in New Zealand.
The electorate also had the highest proportion of people whose family income was either between $30,001 and $50,000 (23 per cent), or between $50,001 and $70,000 (18.3 per cent).