Jacinda Ardern in a flap as tiny bird wins a New Zealand beauty contest

Jacinda Ardern was momentarily ruffled live on air when asked if she had voted for her favourite bird.

A tiny mountain-dwelling wren was the surprise winner Monday of New Zealand's controversial bird of the year competition, which even had Prime Minister Jacinda Ardern in a flap.

The piwauwau rock wren punched above its 20-gram weight, flying under the radar to win the annual contest ahead of popular fellow native contenders, the little penguin and the kea.

Fans of the wren set up a Facebook page to help the outsider soar up the final rankings when the fortnight-long poll closed Monday.

"It's not the size, it's the underbird you vote for that counts," wrote one supporter.

The annual competition ruffled voters' feathers in years past after a native bat was allowed to enter, then won, the 2021 title.

There was also outcry this year after the flightless kakapo -- a twice previous winner dubbed the world's fattest parrot -- was barred from running to give others a chance.

The annual avian beauty contest run by environmental group Forest and Bird is popular with New Zealanders, including the country's top politicians.

The leader of the opposition, Christopher Luxon, took to Twitter -- where else? -- over the weekend to endorse the wrybill, a river bird with a distinctive bent beak.

On Monday, New Zealand's prime minister was momentarily ruffled live on air when asked if she had voted for her favourite bird.

"No I haven't yet -- you can't just chuck a controversial question at me without a warning!," Ardern said with a smile.

New Zealand's leader revealed she will "always and forever" be loyal to the black petrel, which only breeds on the North Island but can fly as far as Ecuador, and she hopes the 2023 competition "will be its year".