There have been three positive cases and two historical cases of Covid-19 reported in New Zealand's managed isolation facilities today.
In a statement, the Health Ministry said there were no community cases and there were now 75 active cases in New Zealand.
Today's new imported cases came from the Philippines, Mexico, Russia and the UK.
In the wake of soaring numbers of Covid-19 cases in Australia, particularly New South Wales, Prime Minister Jacinda Ardern announced yesterday that quarantine-free trans-Tasman travel would cease for at least eight weeks from midnight last night.
NSW has recorded 163 new Covid-19 cases today - the highest number of daily new infections in the state since the Delta outbreak began last month.
As well, the Ministry of Health announced last night that there had been two positive detections of Covid-19 in wastewater in New Plymouth.
The most likely explanation was that the results were due to recently recovered cases continuing to shed the virus, the ministry said.
It said today that it could also signal undetected cases in the community.
"In order to determine whether there are any undetected cases the Ministry is recommending anyone in Taranaki, or who has visited recently, and who has symptoms to get tested.
"Additional testing capacity has been stood up in New Plymouth to support potential demand."
The Ministry has also recommended that any recent arrivals from Australia with symptoms should also get tested, and anyone who has recently been in Australia, and is now in Taranaki, to get tested even if they don't have symptoms.
Meanwhile, managed return flights for New Zealand citizens and those ordinarily resident in New Zealand are being set up for all Australian states and territories.
Those who are eligible to enter the country have been given seven days to return.
By last night Air New Zealand said its flights from Sydney had sold out while a Dreamliner was being added to the Melbourne schedule where demand for seats was also high.
Two states have extra conditions on returning - NSW flyers will still have to return via Sydney and be required to enter managed isolation for 14 days, while those arriving from Victoria will also need a negative pre-departure test and must immediately self-isolate upon return to New Zealand, and return another negative day-three test before leaving isolation.
There were 19 new cases of Covid-19 in managed isolation - all mariners in isolation - and none in the community reported yesterday.
In a statement, the Health Ministry said the country's total number of confirmed cases was 2499.
Sixteen of the mariners had arrived in Lyttleton on the Playa Zahara vessel on 13 July. They were previously reported as being under investigation and are now deemed as current cases.
The other three cases were detected in surveillance testing of mariners, who arrived in Bluff on the MS Mattina vessel on 18 July.