Doctors are warning they will not be able to help all of their patients when there are thousands of daily Omicron infections.
The warning follows the announcement of the Government's three-phase plan to tackle the highly contagious Covid-19 variant.
As the disease spreads, cases will largely manage themselves, rapid antigen tests will become the go-to, and periods of isolation will shrink.
For now, Associate Health Minister Ayesha Verrall said the focus would be on stamping out the virus.
"We are being very intensive about our management of risk while our number of cases are small, but that response can't be sustained when the number of cases are larger."
In as little as two weeks, there could be enough cases to trigger the second phase of the Government's plan - slowing Omicron's spread.
"The system will focus more on identifying those who are at a great risk of severe illness from Omicron [in phase two]," Verrall said.
In phase two, the isolation period will drop to 10 days for cases and seven for contacts.
Critical workers who are contacts of cases will be able to return to work sooner if they can provide a negative rapid antigen test.
Verrall said more cases will be managed digitally.
"Text message notification for positive cases will begin at this stage, with phone support still available for those who need it. Contacts will also be notified via text message."
Papakura Marae GP Matire Harwood visits her Covid-19 patients - usually twice - while they are isolating.
She worried the digital regime would not work for everyone.
"All those people who don't have phones and they're not going to ever use a phone and they're not tech savvy enough to be able to access the website for things like this," she said.
Harwood said people who were vulnerable, or who did want to be a bother, were the biggest worry under the new plan.
"We had seen people dying at home and we didn't want that to happen at all to anybody in our community, so that's been our job to make sure people don't fall through the gaps and it does take more resource."
New Zealand will enter the third phase when there are thousands of new infections every day.
At that point, only those at highest risk will have to isolate. Health officials will focus on managing Omicron's spread in places like prisons and retirement villages. And most community cases will have to manage themselves, with their GP's help.
New Zealand Medical Association deputy chair Vanessa Weenink warned they would not be able to help everyone.
"We need people to be very careful about when they are contacting us, [but] at the same time we don't want people to say 'oh I don't want to bother my GP' so it is a very hard line, but we absolutely will not have capacity if we have tens of thousands of cases a day to be calling people actively," she said.
"We will do what we can, but we will be overwhelmed very rapidly."
As the approach to case management changes, so too will testing, with a focus on rapid antigen tests so PCR tests can be reserved for key workforces.
But National Party Covid-19 response spokesman Chris Bishop said the Government's plan raised more questions than answers.
"When do we move from phase one to phase two? The Government doesn't know.
"What is the definition of a critical worker who can test to go back to work? The Government doesn't know."
ACT Party leader David Seymour said the Government deciding on who was a critical worker and who could leave isolation early was a futile exercise.
"The test for whether you're a critical worker will be 'does my family need a pay cheque' and 'can I afford to take 17 days off?' I think people will say the answer to that is 'no, carry on working and continue to avoid testing positive'."
Seymour said the Government needed to apply a realistic isolation period that people would follow.