The Prime Minister and National Party leader Christopher Luxon faced off this afternoon in Parliament's first Question Time of the year.
Luxon asked if a "cost of living crisis" was underway and what Ardern was doing about house prices.
Ardern said Luxon should recognise Labour inherited a long-term housing crisis and the Opposition leader had offered no solutions on the matter.
She said Labour had put a stop to letting fees, and rental increases for tenants were limited to once a year.
On living costs, she said: "What we have now is not something New Zealand is experiencing alone."
Ardern added: "We join the likes of the UK and the United States ... identifying issues around building more housing and the cost increase in fuel prices."
She said Luxon did not believe the minimum wage should be increased, and he was in no position to "lecture" anybody about living costs.
Luxon said food price increases were the highest in a decade.
Ardern replied: "We are the Government that has, of course, increased things like Working For Families."
Ardern said those payments would increase by $20 a week, whereas Luxon wanted working people to keep working longer and harder with no meaningful wage increases.
Ardern also faced questions from Act Party leader David Seymour, and said she stood by the Government's plan to reopen the borders.
The PM said borders would reopen in the context of high vaccination rates and a booster shot campaign.
"MIQ has been invaluable in protecting New Zealand from the worst of Covid but it has not been without heartache," she added.
Seymour asked why the New Zealand tourism industry would have to wait till late 2022 to fully reopen.
The current Government plan is for the border to fully reopen to visitors from anywhere in the world, and to all visa categories, in October.
Ardern said fully reopening the borders much sooner would exacerbate risks of a major Omicron outbreak, but added: "We do expect there is every chance that date will come forward."
Question Time followed a recent poll showing steady support for the Government as it handled the current Omicron outbreak.
The latest Newshub-Reid Research poll showed Labour up 1.6 points on the last poll in November to 44.3 per cent.
National was up 4.4 points to 31.3 per cent in the first such poll under leader Christopher Luxon.
Both rises came at the expense of Act, which dropped eight points to 8 per cent.
Ahead of Question Time, party leaders marked the 70th jubilee of the Queen.
The clash of the leaders of the country's two largest political parties comes after Parliament opened for the year on Tuesday.
Ardern used her opening statement to Parliament to promise schools and early childhood centres will now only be closed as a "last resort" during Covid outbreaks.
But she also warned that new variants of Covid-19 were expected this year, and the opening of the borders was likely to lead to influenza re-emerging, and it was time to "prepare for winter".
Ardern set out her agenda for the year on the first day of Parliament under red light restrictions - meaning masks around Parliament and only half the full contingent of MPs in the debating chamber at any time.
Luxon took aim at that Covid-19 management, saying although 2020 had been strong, 2021 had been a "shambles".
He dedicated most of his speech to the economy and cost of living, pointed to the rising cost of petrol and groceries, the wage gap between New Zealand and Australia, and the steep increase in house prices.
He also predicted that Labour would end up backing down on its Three Waters reforms, saying Finance Minister Grant Robertson would decide it was too unpopular to go ahead with.
During their first Question Time face-off at the beginning of December, Luxon pushed Ardern on why the Government's $50 billion Covid-19 fund has not significantly increased ICU capacity.
Ardern countered by saying the Government's strategy had been to keep people out of ICU in the first place.
The 19-year-old disappeared without her wallet or mobile phone.