Healthcare experts are calling for the Government to implement more border restrictions after 12 new cases of COVID-19 were detected on Thursday.
Director of Public Health Dr Caroline McElnay announced the cases which were all detected in managed isolation facilities, 10 of which came from the same flight from India on September 26.
"We acknowledge that this is a high number of cases, and it reflects that most of the world continues to experience high levels of COVID-19," she said.
"This also re-emphasises why we have strong border control measures in place, including day three and day 12 testing, to keep New Zealand and New Zealanders safe."
But Dr Michael Baker, a public health professor at the University of Otago, said more needs to be done to protect New Zealand's borders.
"Our border controls are vital to keeping New Zealand free of community transmission of COVID-19," he said.
"It is always necessary to take a comprehensive, risk-based, systems approach to this line of defence. This approach should include considering additional control measures for travellers from countries that are the source of large numbers of imported cases."
Dr Baker said the measures could include requiring a period of pre-departure quarantine and COVID-19 testing for travellers. If they tested positive, their travel should be deferred for a suitable period, he said.
"These measures would of course be in addition to current quarantine and testing requirements within New Zealand. The aim would be to reduce the number of COVID-19 positive travellers who spend time within New Zealand's managed isolation and quarantine facility."
Professor Nick Wilson from Otago University's department of public health agreed the large numbers in new cases "are imposing extra burdens and risks on New Zealand's quarantine system".
"It should prompt serious work by health authorities to lower the risks further," he said.
Prof Wilson said pre-travel COVID-19 testing would help to reduce the burden on our country's quarantine system.
But he said if the New Zealand Government is "really serious about reducing another outbreak" they should stop the use of hotels as MIQ facilities in our biggest cities.
"It should also seriously study the pros/cons of purpose-built quarantine facilities in places such as Ōhakea Airbase. A cost-benefit analysis that took into account the huge economic cost of the recent Auckland outbreak, might tip the balance towards having a high-quality approach to quarantine facilities."
Dr Amanda Kvalsvig, a senior research fellow at Otago University's department of public health added that a review was needed to ensure the border is safe.
"If any loopholes are left for the virus, we can be sure that sooner or later it will exploit them."