Prime Minister Jacinda Ardern spoke to media a day after announcing a suspension of travel from India because of high numbers of Covid-19 cases.

The travel ban will be from 11 April to 28 April and is expected to be temporary.

It is the first time New Zealand has stopped citizens or residents from returning.

"Flights that come in that are before the new suspension is in place, they'll have the same level of precaution and care as we do for every flight, keeping in mind we treat every international arrival as if they potentially have Covid-19. It's always been our practice and that doesn't change," Ardern said this afternoon.

She said New Zealand already had mechanisms in place that she was confident would deal with anyone coming in from high or low-risk countries appropriately.

Over the last two week, over 60 passengers coming into the country from India have tested positive for Covid-19, she said.

There were 90 active cases in managed isolation, so as a proportion of that total number, the Indian cases were relatively high, she added.

"If that number of people from any country were coming in with Covid that would give us cause to pause and look at mitigation to reduce that risk, so this is not country-specific, this is about the cases we are seeing currently from that region," she said.

"Our goal and our approach to all of this has been to bring home Kiwis from abroad and over 130,000 of them have. We have a higher number of people coming back from New Zealand than, for instance, per capita Australia... But I want people to be safe in their journey. At the moment, I cannot guarantee travellers coming from India are safe and not infected with Covid and I want to improve that."

She reiterated that the pause on travel was temporary.

Ardern said the pause offered a window to improve New Zealand's border safety programme, as it had become obvious pre-departure testing was not doing enough to bring down Covid numbers in managed isolation facilities.

"We had put in place day-zero testing as a way of bringing down some of the numbers we were seeing coming through from high-risk countries. We did see an impact from that. We did see our daily rolling average fall away. We have since then seen sustained numbers coming through, particularly from India and it gave us cause for concern as to why our pre-departure testing wasn't having the same impact. So this gives us the opportunity to look at other options to enhance our programme and reduce risk."

"I want people to be safe in their journey," she said.

Ardern warned employers of legal responsibilities to ensure the testing regime was being adhered to.

"The orders make it very explicit, if you are an employer, for instance a private enterprise and your workforce is covered by a testing order, you have a responsibility to make sure they are being tested. There is a penalty regime for employers who are not doing that."

She said the government was responsible for employees of public agencies, not private firms contracted to work at the borders.

One of the issues the government will be probing over the next two weeks will be whether other countries are using the same PCR testing of pre-flight travellers to detect early onset of Covid infection as New Zealand, she said.

This will focus on quality-assurance around other nations' testing regimes.

Ardern says the security guard who tested postive for Covid-19 yesterday did not miss his vaccine appointments due to "vaccine hesitancy". She defers other questions to the Ministry.

The travel bubble with Australia was not made contingent of vaccination levels, she said.

She said the under-scrutiny AstraZeneca vaccine was still being assessed for use in New Zealand and so far only one - the Pfizer vaccine had been passed for use.

"We are still in the process of having AstraZeneca go through our own independent approval process."

Yesterday a security guard at the Grand Millennium managed isolation and quarantine (MIQ) facility in Auckland was reported as having Covid-19, and there were another 23 new cases in managed isolation - 17 among arrivals from India.

Ardern was speaking after attending the opening of the National Telehealth Service Auckland Centre with ACC Minister Carmel Sepuloni, Health Minister Andrew Little and Associate Health Minister Ayesha Verrall. The services include advice or support on health, drug and alcohol issues, mental health, depression and anxiety.