One half of a large elective surgery centre has been temporarily closed so staff can be diverted help Middlemore Hospital.
There are 142 Covid-19 patients in the hospital, more than in any other, and 400 frontline staff off work because they are sick or isolating.
About one in four patients turning up to the emergency department is testing positive for the novel coronavirus.
A nurse who works at the Manukau Surgery Centre, which mostly does elective - or planned - surgery for Counties Manukau DHB said one of the two wards there was not running.
That meant some non-urgent operations had been called off, although surgery for serious cancers and other conditions that could not be delayed was still going ahead.
It was often orthopaedic operations that were deferred, she said.
Even though they were not classed as urgent, the operations would be life-changing for many patients who may be in pain when they walk or unable to work, she said.
"For them, emotionally and psychologically having to delay that surgery could could have a big impact on them."
Counties Manukau chief medical officer Andrew Connolly stressed that everyone who needed hospital care, including surgery which could not be delayed, would get it.
But deferring some operations helped ease the pressure on the hospital, he said.
For example, surgeons were now working more directly with emergency departments to help move people through more quickly.
"If someone comes in with significant abdominal pain, the general surgeons will pick that case up earlier than our traditional approach which would be for that patient to be seen by the emergency department staff," he said.
Orthopaedic and plastic surgeons would work in a similar way, he said.
Connolly was hopeful case numbers at Middlemore would not double in the next few days as has been predicted for hospitals nationally.
But if they did, there was the option to cut more services and to move patients to the city's other hospitals, he said.
The biggest staffing challenge had been in nursing, but those working had managed to keep the ward care to a very high standard.
"It's not a barrel of laughs and everyone's tired but they're doing a bloody good job," he said.
The Nurses Organisation said some ED nurses had been copping abuse, which was adding to their stress.
Union organiser Christine Gallagher had regular check-ins with the teams she looked after in ED and medical wards and said one nurse told her the was an "astronomical" amount of abuse.
Mostly, it was from family members upset at the hospital's visitor restrictions, she said.
Nurses were also feeling the stress because staffing was "on a knife edge", with many of their colleagues of off sick or caring for family members.
"Every day is different, there'll be some days where there are lots of patients at the door and everybody's struggling and they can't cope and they're running around, and other days where it is manageable," she said.
Between 60 and 70 percent of Covid-19 patients in Middlemore were there because of the virus, with the rest found to have it when they presented for other reasons.