All three of Auckland's main hospitals are building more negative pressure rooms to keep up with the Delta strain of Covid-19.
The city's district health boards have revealed details of the work that is going on at the same time as they treat 32 Covid-19 patients between them, eight in intensive care.
A DHB spokesperson said the negative pressure rooms were being built at Middlemore, Auckland City and North Shore hospitals in general wards, intensive care units and emergency departments.
A spokesperson for the Intensive Care Society, Andrew Stapleton, said there were not 30 ICU nurses spare around New Zealand.
There had been shortages for years.
If they were all needed, services in other parts of the country would likely be hit, he said.
Some of the country's ICUs are not full because they have been at alert level 4 but may not be able to resume normal service if their nurses had to go to Auckland.
It was good planning by the Auckland DHBs to ask for more staff but they may not need them, he said.
General nurses were also being recruited to help in managed isolation facilities.
Health authorities have rejected criticism that they should have been more prepared for the possibility of another major outbreak, saying the current moves are part of their surge plans.
A DHB spokesperson said they had plans in place for some time and had been amending them as they learned more about the infectious Delta strain.
There were currently 40 negative pressure rooms across the city, 17 at Middlemore, 13 at Auckland and 10 at North Shore.