United Future's former long-time leader Peter Dunne says the end of the party is "sad, but understandable".
A letter sent out to members this week said the party's leadership had voted to disband after it received just 0.1 per cent of the vote in this year's general election.
The centrist party had survived on the back of an electoral deal in Ohariu between Mr Dunne and the National Party - but Mr Dunne's resignation this year, sparked by poor poll numbers - meant it failed to return to Parliament.
His successor, Damian Light, last night confirmed the party's demise.
"This decision has not been made lightly and has been debated at length," he said.
However, the motion was passed unanimously at the weekend's annual general meeting in Auckland.
It had become clear the party was not capable of reaching the 5 per cent threshold to re-enter Parliament, Mr Light said.
Mr Dunne - who held the Ohariu seat from 1984 until 2017 - has told 1 NEWS he's sad but thinks it was an understandable decision by United Future.
"And in the context of not having a seat in Parliament anymore, probably it was going to be a bit uphill for them to make a comeback as they were. So altogether not surprised," he said.
We've been part of governments for the last 15 years, so I think that's a pretty solid achievement- Peter Dunne, former United Future leader
Mr Dunne wasn't at the meeting but said if he was, "I think I would probably have said look, it's time to take stock. Is this the right vehicle still? Does it need to be rebranded or does it need to be taken apart and rebuilt? So I think from what I gather they were the sorts of issues that were canvassed and I'd have certainly raised them had I been there".
United Future was the product of a merger between the centrist United New Zealand party and the conservative Future New Zealand party for the 2002 election.
It won eight seats that year but its support dwindled to a single seat by 2008. Mr Dunne was its only MP since then.
"We've been part of governments for the last 15 years, so I think that's a pretty solid achievement," he said today.
Mr Dunne says changes need to be made to MMP to ensure smaller parties have more of a shot of making it into Parliament.
"The one thing that worries me about this election was the fact that all of the minor parties - ACT, the Maori Party, United Future - got squeezed very badly. We're returning to First Past the Post by stealth and I think that's not what people had in mind when they voted for MMP," he said.
Meanwhile, Mr Light says he is personally interested in staying in politics and has floated the idea of joining other parties or starting a new one.