The government will remain "cautious" when it comes to the border and has no plans to change the 14-day quarantine, Health Minister Chris Hipkins says.

Hipkins has replaced David Clark who announced his resignation yesterday, after a tumultuous few months in the role.

Responding to a call by three influential New Zealanders for a a pragmatic strategy to reopen the country's borders, Hipkins said New Zealanders did not want to see cases of Covid-19 flooding across the border.

Sir Peter Gluckman, the former chief science adviser, former Prime Minister Helen Clark and ex Air New Zealand chief executive Rob Fyfe have co-authored a paper about how New Zealand could begin to open up.

Sir Peter told Morning Report that at some time in the near future the government had to have a strategy in place of gradually opening the border.

Hipkins said New Zealanders wanted to lock in the gain the country has made.

"Those countries that have eased off and said 'lets figure out how we can live with this' have ended up experiencing further outbreaks and in some cases have had to move back to more of a lockdown phase.

"That's something that we want to avoid here in New Zealand, so we are going to be cautious around what we do at the border."

He said New Zealand had more ability to get people back to work than many other countries because there were no lockdown restrictions.

The government had no plans to change the 14-day quarantine, and would look to expand managed isolation and quarantine capacity.

National Party health spokesperson Michael Woodhouse has questioned whether Hipkins will be able to do justice to his new role.

He said the minister now had a huge workload, and the decision to appoint him to the health portfolio showed the lack of depth around the Cabinet table.

"He has two of the largest portfolios in Cabinet and it's just not possible to do justice to both even in the period leading up to the election."

"We've got now Dr Megan Woods and Chris Hipkins being loaded with portfolios. There are three associate health ministers and the prime minister has seen none of them as worthy of coming into the health role even in a holding basis so I think that speaks volumes to her confidence in them."

Woods has taken on major aspects of the Covid-19 response including testing at the border in addition to her role as Housing Minister.

Hipkins said responding to Covid-19 required the focus of the entire government.

"Between Dr Woods and I, you'll see a very rigorous focus on testing of all the advice we receive around what's happening at the border. We'll be looking very closely at all of the other aspects of the health response.

"Being minister, whatever the portfolio you're in, is ultimately a leadership role. I believe that I can provide leadership that's need for both of those portfolios.

"It's going to be a challenge - I'm always up for a challenge - it'll require careful time management and I think I'm pretty good at that too."

Hipkins said National MP Hamish Walker's remarks on returning New Zealanders were a "dog whistle" by invoking nationality and country of origin.