The government should consider banning flights from the United Kingdom and other countries where Covid-19 is out of control, says an epidemiologist.
Almost a quarter of New Zealand's active cases are now the UK variant, with that amount expected to increase.
Australia is tightening its managed isolation and quarantine (MIQ) rules after the UK variant was found in its community.
Epidemiologist Nick Wilson told RNZ's Summer Times New Zealand should do the same as the variant was far more contagious.
The professor of public health at the University of Otago said the government should consider banning flights from some countries and look at fast-tracking vaccinations for border control workers.
"The change in the virus has made it more infectious, the world is really grappling with it and we are seeing greater spread of Covid-19 in many countries," Prof Wilson said.
"As a result, we are seeing more infected people at our border - this is a very serious situation."
He said 31 cases arriving over the last three days was a high figure.
"Given our system for controlling this disease is all at the border and it is no where near perfect this could lead to an outbreak," Prof Wilson said.
"We have had at least seven border failures in the last six months associated with MIQ facilities, including the large Auckland August outbreak."
The government needed to take a careful look at what to do next, Prof Wilson said.
"It's probably time the government bans flights from the US and the UK until the situations in those countries improve, the risk is just too high."
From 15 January, travellers from the UK and US will need a negative test result for Covid-19 before departing for New Zealand. It comes in addition to the day one testing the government introduced as an extra precaution at the border.
National Party calls for vaccine rollout to be fast-tracked
The Ministry of Health said the first lot of vaccines will be ready in the second quarter of this year.
National Party leader Judith Collins said with the highly infectious UK and South African variants showing up at the border, it was critical border workers were vaccinated as quickly as possible.
"Australia recently brought forward its vaccine rollout, with health workers, border personnel and aged-care residents at the front of the queue," Collins said
"New Zealand has fallen behind the rest of the world with its vaccine programme and the government needs to explain why."
She said Canada had enough vaccine to cover each citizen five times over.
"Meanwhile we've heard nothing from our government, we need to know how many doses they've ordered, when they're arriving and if the whole thing can be fast-tracked.
"Kiwis are rightly asking why Australia has plans to vaccinate four million people by the end of March while New Zealand won't start vaccinating the general public until at least July."
The government has secured various deals for vaccines, including for 7.6 million doses from AstraZeneca - enough for 3.8 million people, 10.72 million doses from Novavax - enough for 5.36 million people, 750,000 courses from Pfizer/BioNTech, and 5 million from Janssen.
If the vaccines are proven to be safe and effective by MedSafe, then priority will be given to vaccinate border workers, essential staff and their household contacts.
The government has been approached for comment.
But in December, Minister of Health Andrew Little said MedSafe had agreed to allow pharmaceutical companies to make rolling applications for their Covid-19 vaccines, which means they may submit their data as it is completed and ready for assessment to speed up the process.
"New Zealand has never before attempted an immunisation programme of this scale and complexity," Little said.
"Workforce planning to ensure we have enough vaccinators is well advanced. There are around 12,000 health professionals already able to administer vaccines and more will be trained."
At the end of last year, Prime Minister Jacinda Ardern told RNZ a vaccine rollout would "take some time" and won't look anything like past vaccination programmes in the country, where you have all of the vaccines you need for the whole population and run one single campaign.
"So a lot of planning and preparation is going into what that will look like next year, and at the same time, we'll need to keep in place measures that match the rollout of that vaccination to keep people safe while we're going through that.
"There are limitations to the numbers that are being produced, and some countries are rolling out very early when we still have data that's demonstrating, you know, the potential of these vaccines. And they're doing that because, of course, they're losing lives now. So of course are building that into the calculation."
She said comparatively, New Zealand was in a "different scenario".