The Government is suspending compassionate exemptions from managed COVID-19 isolation, in order to ensure the system is working as intended.
It comes as two new cases were confirmed in New Zealand on Tuesday as two women who recently arrived from the UK via Australia were permitted on compassionate grounds to leave managed isolation.
Health Minister David Clark said on Tuesday evening compassionate exemptions should be "rare and rigorous" and said it "appears that this case did not include the checks that we expected to be happening".
He described it as "not acceptable", adding that New Zealand's border measures are a "key line of defence against COVID-19 and we must ensure they are as robust as possible".
Dr Clark said Health Director-General Dr Ashley Bloomfield will be reviewing the processes around the latest two cases.
"He has already made it a requirement that all individuals must return a negative COVID test before leaving managed isolation facilities from now on."
Dr Clark has also asked Dr Bloomfield to consider if there are any other measures the Government can put in place to strengthen health protections at the border.
"New Zealand remains in an enviable position and the risk to the public remains very low – but as Health Minister I want to ensure we are doing all that we can to keep COVID-19 at bay."
The Ministry of Health said the two women arrived in New Zealand together on 7 June and stayed in a managed isolation hotel in Auckland, before being permitted to travel to Wellington via private vehicle on 13 June.
The ministry said there was an agreed plan in place as part of the compassionate grounds, including for the travel. Both women followed the conditions, including not having contact with anyone on the journey or using public facilities.
One of the women experienced mild symptoms of COVID-19 while the the other was symptom-free.
The ministry said both presented for testing at a Wellington community assessment centre as part of their agreed self-isolation plan.
Following their positive results, local public health staff are testing and isolating all others who may be at risk of exposure, and in this case, it is one additional family member.
Potential contacts include people on the same flight from Brisbane, and people who are in or have been in the same managed isolation facility, including staff.
The contact follow-up is being managed by the national contact tracing unit at the Ministry of Health, with support from the local DHBs.