Health authorities said the outbreak had peaked in Auckland but was still growing nearly everywhere else.
Pinnacle Midlands Health Network has 85 practices across the middle of the North Island and medical director Jo Scott-Jones said some were seeing huge numbers of patients with the virus.
There were surges in Taranaki, Tairāwhiti, Lakes and Waikato DHB areas, he said.
"What we're seeing is being described as a Mexican wave, sort of travelling down the country," he said.
Many practices were so busy with cases and staff absences they were having to stop routine appointments to focus on urgent and Covid-19 care.
Some were able to get around the problem to a degree by caring for patients over computers or the phone, he said.
Director-General of Health Ashley Bloomfield said there were encouraging signs the outbreak was about to peak in Wellington and the central North Island but was still on the rise in other places, particularly the South Island, he said.
Auckland emergency specialist Dr Kate Allan warned the outbreak was not over for the city despite the peak.
"There is a very long tail to this and the daily presentation numbers will continue to be high," she said.
"Even though we've reached the peak, my understanding from an epidemiological point of view is that we still have half the cases ahead of us."
Figures from the city's DHBs show the number of people turning up to most emergency departments with the virus this week had halved from previous highs.
Despite that a quarter of children at Middlemore's Kidz First ED still had the virus, and a fifth of children at Starship's ED.
In adult emergency departments, a fifth of people presenting to Middlemore were Covid-19 positive, 17 percent at Auckland City Hospital, and 13 percent each at North Shore and Waitākere.
The daily average number of people in the city's hospitals was about 200, with little change over the past few days.
Dr Allan said because the hospital wards were so full, the emergency departments remained busy.
Patients were often queued up, waiting for a ward bed to become available, a problem that had existed long before Covid-19, she said.
She said not many staff were off sick with Covid-19 but still enough to create difficulties, especially because of existing shortages.
The spike had been very tough but it would have been much worse without the high vaccination rate and the huge work done by health staff in the community including Māori and Pasifika health providers, GP clinics, Healthline and Whānau HQ.
"Those people have really borne the brunt of this surge and protected emergency departments," she said.
Dr Scott-Jones said it was nurses who were busiest in many rural practices, working hard to check in on patients.
Most people were managing well at home and but some were very anxious, he said.
Both doctors said health services would need to work out how to keep managing throughout the year when Covid-19 would remain in the community.