The Labour Party has lost some support in the first political poll of the year - but its leader Jacinda Ardern has been dealt a significant, personal blow.

She is down 15 percentage points on preferred Prime Minister rankings in tonight's 1News/Colmar Brunton poll.

She's sitting at 43 per cent - which is still significantly higher than her main rival, National's Judith Collins, who's a 8 per cent - that's down 4 percentage points on the last poll.

Meanwhile, former leader Simon Bridges has appeared on that list - sitting at 1 per cent.

But he is behind National's Chris Luxon, who's at 2 per cent.

Meanwhile, the Labour Party is down 4 percentage points to 49 per cent - that's far ahead of National's 27 per cent, that's down 2 percentage points.

In terms of seats in the House, Labour still have a majority with 62 seats.

The Greens are up slightly to 9 per cent and Act is steady at 8 per cent.

The Māori Party is up to 2 per cent, the poll shows.

Speaking to TVNZ, Ardern said she was still pleased at the level of support she is getting.
"I do have to make some tough calls and they do impact on people's lives, but I still feel really heartened to have the support too."

On the increase from 25 per cent to 27 per cent, Collins said National was beginning to "trend a little bit in the right direction".

"But there's a lot more work to do."

Asked if she was nervous about a leadership challenge based on her preferred PM rating being in single digits and her party in the 20s – Collins said, "not at all".

Tonight's poll is the first since December last year. Those numbers showed that Labour had a commanding lead over National. Labour was sitting at 53 per cent while National was at 25 per cent.

The December poll was taken roughly two months after the election where Labour won an outright majority in the House and formed a Government.

On that poll, both Act and the Greens were at 8 per cent and the Māori Party was on 2 per cent.

New Zealand First, which was booted out of Parliament by voters at the election, was on 2 per cent.

Since the last poll, Auckland has been into lockdown twice after Covid-19 was discovered in the community.

In the past, voters have been supportive of Prime Minister Jacinda Ardern's leadership through these times.

However, in the most recent lockdown – when Auckland went to level 3 for seven days – questions were raised about the Government's communication.

Even Brian Roche – the man appointed to chair the group which monitors the Government's Covid-19 advice – said that there was "mixed messaging" at play.

This has been an issue that National has been critical of the Government over.

In December, Jacinda Ardern was at 58 per cent in the preferred PM stakes while Judith Collins was at 12 per cent.

She was followed by Act leader David Seymour at 4 per cent and National's Chris Luxon at 2 per cent.

Tonight's poll is the first 1News/ Colmar Brunton poll not to use landlines.

In the past, there had been a 60/40 split – but tonight's numbers won't include a single poll taken from a landline.

Tonight's poll was done using 50 per cent randomly generated mobile phone numbers and 50 per cent online from New Zealanders who have signed up for market research studies.

"People just aren't using landlines like they used to," said 1News political editor Jessica Much McKay.

"Pollsters are finding people pick up their mobile phone more regularly so it's easier to get in touch."