Hospitals are being told to consider putting off surgery for seriously overweight people and those over 70 unless it is urgent.
A memo from the Ministry of Health to district health boards has outlined how they should manage getting normal services up and running again with the risk of Covid-19 still looming.
It said deferring treatment should be considered for people over 70, those with a body mass index over 40, or those with other conditions including heart, lung or kidney disease.
That is because if they contracted Covid-19 they had a higher risk of death.
But if they urgently need treatment, they should get it, the memo said.
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Whanganui DHB said it would not be doing surgery for people over 70 or those with conditions that put them at extra risk.
And Wairarapa DHB said it would not do surgery on elderly patients until level 2, unless it was urgent.
RNZ asked all DHBs about any restrictions they have as they tried to resume normal surgery and treatments.
Not all of them specified age but some said they would follow the ministry's guidelines.
Hawke's Bay DHB said it had no restrictions on those over 70.
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The ministry is urging DHBs to return to "planned care" which includes non-urgent elective surgery and specialist appointments.
But they should only do that where they could still have measures to avoid Covid-19 in place, it said.
And in another document sent to DHB chief executives, the ministry warned of a "bow wave" of demand as services got up and running again.
There were an estimated 60,000 specialist appointments cancelled nationwide, it said.
However, that figure did not include the thousands more that would likely have been made over that period.