Health experts believe the government's decision not to impose mandatory pre-departure tests for international travellers is the right call.

It follows growing global concerns about the Covid-19 case numbers out of China and concerns by authorities such as the World Health Organisation (WHO) about a lack of reliable data out of the country.

Covid-19 Response Minister Ayesha Verrall says officials had done a public health risk assessment and concluded there was minimal risk to New Zealanders.

In an announcement yesterday, Verrall acknowledged the WHO's concerns and says the government would be asking travellers arriving from China to help gather more information.

This would include e-mails to a random sampling of recent arrivals from China to ask them to undertake a voluntary rapid antigen test (RAT) and share it with authorities.

Verrall says BF7 was the prevalent variant in China and had not caused significant outbreaks in other countries that, like New Zealand, had already been exposed to the BA5 variant.

University of Otago epidemiologist Michael Baker described the move as a "complex and finely balanced decision".

University of Otago epidemiologist Michael Baker. Photo: RNZ.

But he says some future planning was required around how testing of international visitors was managed.

"Situations where countries are experiencing a surge of cases, or potentially, a more dangerous new variant," he says.

"We don't actually have that at the moment.

"Given the way this virus is continuing to evolve, I do think we need to have a strategy for what we're going to do about new variants and surges of new cases coming across the border."

Travellers from China to Australia would be required to have a negative pre-departure test from today, joining the likes of the United States, the United Kingdom and Canada.

Baker says although there were benefits to pre-departure testing, it should not just be about China.

"I think it is a pity that China is being singled out in this instance," he says.

"I think it's more about the principles of biosecurity.

"At what point will we require relatively simple pre-travel measures, like requiring supervised RAT tests before people get on flights.

"There must be circumstances when we would say 'actually that makes sense'."

ESR scientists would also pilot wastewater testing from international flights in the coming weeks, which could replace the targeted and temporary voluntary testing announced yesterday for travellers from China.

University of Auckland microbiologist Siouxsie Wiles says the government's announcement was a "sensible response", but called for more measures within New Zealand's borders.

"We aren't doing enough in my opinion to reduce transmission," Wiles says

"I think we should be having masks on public transport, and supermarkets and retail," she says.

"We really need to be dealing with the issue of ventilation ... clean air.

"We know this virus spreads through the air and masks and ventilation are things that would work for any variant."

Wiles says moves to impose travel restrictions solely for China, and not other countries, was a case of "xenophobia".

"We've seen it happen during the pandemic where certain countries have been targeted, and it hasn't worked."

Opposition political parties also welcomed the government's announcement.

National Party MP Simeon Brown says it was good to see advice from health officials being followed.

"To support public confidence in decisions like this, the government should release the health advice the decision was based on," he says.

ACT leader David Seymour says pre-departure testing was "no silver bullet".

"The effect of pre-departure testing on New Zealand case numbers would have been negligible," says Seymour.

"The effect on Chinese Kiwis eager to see family, and tourism operators wanting to get Chinese customers back would have been major inconvenience for little benefit.

"This is a sensible position instead of importing 2020 panic into another new year."

- RNZ.