There are no new cases of Covid-19 in New Zealand.

That means the total number of cases in the country remains 1492. No one is in hospital with the virus. It comes after one person had been held in isolation on a general ward at Middlemore Hospital for several days.

Ten previously reported cases are now considered to be recovered, Director of public health Dr Caroline McElnay said.

This morning Health Minister Chris Hipkins announced a new suite of measures for aircrew to come into force next week.

Overseas-based air crew who are laying over in New Zealand will be required to stay in a Government managed isolation facility for as long as they are in the country, to ensure they avoid contact with New Zealanders

They will be required to wear PPE on flights, in airports and whenever travelling between the airport and their hotel. They will also isolate with other crew members while on overseas layovers.

New Zealand-based crew returning to New Zealand from high-risk locations overseas will be required to self-isolate for at least 48 hours after they return, and until they are assessed as being low risk of having Covid-19.

The new measures are part of a public health response order that will come into effect from 11.59pm this Sunday.

It comes after it emerged yesterday that 12 people in managed isolation had tested positive for Covid-19 - 10 were on the same flight from India on September 26.

It has prompted Otago University epidemiologist Professor Michael Baker to push for a week in quarantine and a negative test before travellers can fly into New Zealand from Covid-risky countries.

The National Party has also been pushing for a pre-departure negative test, but Labour leader Jacinda Ardern remains lukewarm on a pre-departure test, saying it would "not necessarily" strengthen New Zealand's overall response.

"People often could have Covid and not test positive. They have to have had it for a period of time before they test positive," Ardern said yesterday.

But she hinted a pre-departure test was something that could be looked at in the future, when it was easier to have it done.

"In India, specifically, one of the issues has been the ability to test pre-departure. We would literally have to have health people on the ground in order to do that," Ardern said.

"It's one extra element, but not necessarily something we can deploy at every border at this stage."

People would still need to stay in managed isolation or quarantine for 14 days and test negative before leaving, she said.

The latest group tested positive around day three of their time in managed isolation. All have been transferred to the Jet Park Hotel quarantine facility.

The 10 cases were spread out on the plane, sitting between rows 14 and 41.

Before people boarded flights in India, they were being checked to see if they were symptomatic, McElnay said yesterday.

The journey from India was flown by Air India, and its international crew went into managed isolation when they arrived - which is now standard practice.

Baker told RNZ this morning he supported a pre-departure test and one week in quarantine before flying out for countries with large Covid-19 outbreaks.

If their pre-flight test was positive, they would need to delay their departure to New Zealand by a month.

"The goal here is not to stop every case. It's to reduce the number arriving in New Zealand which puts a strain on our system," Baker said.

"This is all about probability, it's about decreasing the risk of anyone getting through this managed isolation system in New Zealand."

Reti pointed to another flight from India where 17 people on board tested positive.

"Pre-departure testing effectively pushes our border offshore and strengthens our protection from coronavirus," Reti said.

"Labour can't let bloody-mindedness stand in the road of strengthening our border."