UPDATE: Prime Minister Jacinda Ardern says the incident that saw two new COVID-19 cases leaving isolation "should never have happened and cannot be repeated".

Speaking to media to address actions taken by the government in response to two new COVID-19 cases announced yesterday, Ardern says the case represented "an unacceptable failure of the system".

"From the beginning, we have taken an extraordinarily cautious approach at the border ... that is also why we required tests to be undertaken at those facilities - one at day 3 and one at day 12.

"That should have happened in the cases we learned about yesterday, it did not and there are no excuses."

The Prime Minister is appointing assistant chief of defence Air Commodore Digby Webb to oversee all quarantine and managed isolation facilities.

Webb will also undertake an audit of all the existing systems and written protocols to ensure they were being fully implemented.

Ardern says the suspension of compassionate exemptions will continue "until such time as we can guarantee a disciplined and rigourous system at the border that ministers have confidence in".

She says there has been pressure from many corners to relax the rules for compassionate exemptions.

EARLIER:

Prime Minister Jacinda Ardern is speaking to media to address actions taken by the government in response to two new COVID-19 cases announced yesterday.

Ardern is expected to speak from 1.30pm.

Director-General of Health Dr Ashley Bloomfield yesterday revealed the two new cases to be two women who arrived from the UK on Sunday 7 June, and were granted a compassionate exemption to leave managed isolation in Auckland to visit their dying parent in Wellington.

Health Minister David Clark yesterday temporarily suspended the exemptions after the news.

The Chief Ombudsman Peter Boshier has since announced inspections at all COVID-19 isolation and quarantine facilities set up for people arriving from overseas.

Boshier says at one hotel, new arrivals in the country were able to mingle with other guests, including his staff.

Opposition leader Todd Muller told RNZ's Morning Report today the stakes were too high for the rules not to be followed, and has called for Clark to be sacked over the management of the women's case.

-RNZ