It is Ardern's lowest approval rating in this particular poll - even Judith Collins once had a higher score, hitting +27 in July 2020 - and she is perilously close to Todd Muller's +10 in a June 2020 poll.
Her rival, new National leader Christopher Luxon, made his first appearance in the poll with a net approval rating of 22 points.
However, Luxon won't be celebrating just yet. His performance in the poll was bolstered by the 37% of people who either didn't know whether they approved or disapproved of him, or declined to answer.
The poll showed 42% of people approving of Luxon and 20% disapproving.
Another reason for Luxon not to get too comfortable is the same poll showed support for Labour still a long way ahead of National, which could not form a government on these numbers.
National is on 32% in the poll, trailing Labour's 40%. Act scored 11%, and the Greens, 6%, giving the left-leaning parties the numbers to form a government.
Ardern was dragged down by results showing her to be increasingly polarising: more people both approving and disapproving of her - 57% of respondents said they approved, 37 said they disapproved.
Just 10% gave no answer or said they didn't know, which is probably to be expected given Ardern has been prime minister for four years - most people have an opinion on her one way or the other.
Ardern's rating is possibly hampered by the long Delta lockdowns in Auckland and uncertainty over the future with Omicron.
She still has significant support among Labour supporters, who give her a 90% approval rating, and Wellingtonians, 65% of whom approve of her.
Ardern appears to have lost support amongst the wavering National voters who delivered her an historic majority at the 2020 election.
The groups that are more likely than the average New Zealander to disapprove of Ardern include Pakeha, 41% of whom disapprove of her, and people with a household income of more than $100,000, 46% of whom disapprove of her.
Luxon's support comes from National and Act supporters, and people with household incomes of above $100,000, 57% of whom support him.
He also enjoys above average support among men aged 35-54, 56% of whom support him.
He is most strongly disapproved of by Green and Labour supporters, as well as people with a household income of below $30,000, 28% of whom disapprove of him.
The poll ran from Saturday 22 until Wednesday night and polled 1000 eligible voters. The maximum sampling error is approximately ±3.1 percentage points at the 95% confidence level.
