There are four new Covid cases to report today, all in managed isolation facilities.

The four cases in MIQ have come from Pakistan, the Philippines, Indonesia and India.

The total number of active cases in New Zealand today is 25.

Today's announcement comes after four new cases were identified in managed isolation yesterday, since the Ministry of Health's last update on Friday.

Brisbane breach: All passengers contacted

Meanwhile all 397 passengers aboard three flights to NZ which left Brisbane International Airport after the green zone breach on April 29 have now been contacted.

"A further two people have contacted Healthline over the weekend to say they were in the locations of interest at Brisbane Airport at the relevant time," the Ministry of Health said.

"This means there are now 29 people considered casual plus contacts who have been asked to self-isolate and get tested five days after their exposure.

"The remaining passengers who weren't at the locations of interest at the specified times are advised to monitor their health and if symptoms develop, call Healthline and get a test."

The ministry said the risk from this event continued to be assessed as low.

Western Australia cases

Officials are continuing to monitor developments in Western Australia after a Perth managed isolation facility worker and two of their housemates tested positive for Covid-19 at the weekend.

New Zealand health officials have determined the risk to public health in New Zealand from these cases is low.

So far, no one who has arrived in New Zealand has contacted Healthline to say they were at any of the 17 locations of interest currently connected to these cases at the specified times.

Western Australian health officials are continuing their scoping interviews of the two housemates and it is possible further locations of interest could be added.

Also today, the Auckland Airport worker believed to have been infected with Covid while cleaning a plane has now returned a negative test in day 12 of quarantine.

"This case is now considered closed," health officials said.

PM to make Cook Islands bubble announcement later today

There is speculation in the Cook Islands that Sunday, May 16 (NZT) is understood to be the day a two-way travel bubble will begin with New Zealand. The date is set to be announced by the NZ Government after a Cabinet meeting this afternoon.

Prime Minister Jacinda Ardern said the announcement this afternoon would bring "ultimately good news" for both New Zealand and the Cook Islands.

No new historical cases - which are not considered to be infectious - have been reported either.

Authorities also had more good news to share; in that four people who were previously reported to have contracted the virus had since recovered.

As of yesterday, the total number of active cases in New Zealand stood at 24.

The total number of confirmed cases in the country was 2262.

Since January 1 of this year, 50 historical cases have been reported - out of a total of 446 cases.

Today's update, in the form of a statement, comes after flights between Perth and New Zealand resumed today after new confirmed cases were found in Perth over the weekend.

A security guard at a managed isolation and quarantine facility tested positive for the virus in Perth. Later, officials there confirmed that his two housemates had also tested positive for Covid-19.

The scare resulted in direct flights from the city to New Zealand being grounded as authorities in Perth tried to work out whether or not the virus had spread further into the community - and if a sudden lockdown needed to happen as a result.

A meeting was held between Australian and NZ health officials yesterday to assess the situation and concluded that the risk to public health in New Zealand was low.

Flights would be able to start again from today, Kiwi authorities said.

However, anyone in Australia - including New Zealanders - who had been at one of the locations of interest identified in Perth cannot travel to New Zealand within 14 days of that exposure.

People who have been in Perth from April 27 are asked to check the Western Australian Government website for locations of interest and ongoing advice about needing to be isolated or getting tested.

New Zealand's Ministry of Health officials were also worth to contact anyone who arrived in the country from Perth from that date.

Meanwhile, yesterday's update also showed that just over two million Covid tests had been processed by laboratories.

The seven-day rolling average up to yesterday was 3729 tests processed.