Chris Hipkins knew Jacinda Ardern was considering resigning late last year

Incoming Prime Minister Chris Hipkins says he was aware Jacinda Ardern was thinking about stepping down late last year. 

Ardern announced she was resigning from the top job at the Labour caucus retreat on Thursday.

She said she has given her absolute all but doesn't have enough in the tank for another term. 

The Prime Minister's resignation came as a shock for many because she had repeatedly offered assurances she had no plans of leaving. 

But Hipkins has revealed Ardern started considering leaving the top job late last year.

"We've had conversations over a period of time. She confirmed with me sort of about a week before we got together…"

AM co-host Ryan Bridge then questioned whether Hipkins knew last year, to which he said he was aware Ardern was "considering whether she had enough to keep on going". 

Bridge then questioned whether this meant Hipkins has had "quite a long time to think about what your government might look like". 

"No, I've had an opportunity over the summer to take a break and I wanted to do that because I also knew that if I was going to take on a bigger challenge this year, I wanted to make sure I was coming back re-energised and refreshed," Hipkins told Bridge. 

"So to some extent, I wanted to make the most of that opportunity because I don't know. There'll be much more of an opportunity for that in the next nine months. And so I have made the most of that." 

Hipkins also defended his credentials as the new leader on Monday, when Bridge questioned whether he had enough financial knowledge to lead the country through the tough economic challenges that are on the horizon. 

Hipkins said he did and offered assurances Grant Robertson would remain as the Finance Minister to help guide the Government. 

"Grant Robertson is going to be our Minister of Finance. I'm here to lead the Government. I think if you look at the work that I have done as a Minister, I can grip up a policy brief quite quickly when I need to, but Grant is going to continue to lead our economic strategy," he said. 

Hipkins also said he brings an "understanding" of what everyday New Zealanders are facing. 

"They're going to be concerned about the mortgage interest rates. They're going to be concerned about how much it costs to buy stuff at the supermarket. They'll be concerned about their power bill, their petrol bill. Those are things that I understand," he said. 

"I understand what the issues are that are driving New Zealanders, and I want to make sure that my Government is absolutely focussed on those core bread and butter issues that are important to New Zealanders."

Hipkins was confirmed as the new Prime Minister on Sunday after he was the sole nominee for the Labour Party leadership. 

And he has the stamp of approval from the country's outgoing Prime Minister with Jacinda Ardern saying Hipkins will be "absolutely fantastic".

"I have known him for a number of years. I have worked alongside him closely. He will do an exceptional job. To see the caucus be absolutely united in their support for what will be a fantastic Prime Minister, I am delighted," she said on Sunday.