"It's right through the emergency department from reception staff, security staff, nursing staff, health care assistants, junior doctors, senior doctors, and then allied health services as well like radiography and lab workers, paramedics as well. So it's widespread."
About 800 doctors and nurses at Wellington's three hospitals have been off sick or in isolation this week - nearly 15 per cent of the clinical workforce.
With the Omicron outbreak yet to peak, front-line health workers warn it is more critical than ever to slow the spread.
Wilton said about two-thirds of Covid-19 patients were coming to ED because of their coronavirus symptoms, while others were seeking treatment for unrelated problems - including broken ankles, back pain, strokes, or seizures - and incidentally tested positive.
"Interestingly, a small proportion refuse to be tested for Covid, so there's that to deal with as well."
Staff were working extra shifts and longer hours, she said.
"I am really fortunate to work with a group of really dedicated people. It astounds me how deep they can dig. But I think people are really tired."
Morale had also been hurt by stalled contract negotiations, including the zero per cent pay offer to senior doctors by DHBs last year, she said.
"Comments by the DHBs' negotiating team that health workers must have their 'year of pain' were not especially helpful.
"Nurses also want to see progress on their request for safe-staffing levels. That would really show we're appreciated."
A senior nurse, speaking anonymously, said Wellington Hospital was already understaffed before the pandemic, but it had got much worse.
"Nurses tend to want to look out for each other, so they'll come in if they're not feeling particularly well just to make sure their colleagues aren't left really, really short-staffed.
"There are constant texts going to staff members to come in and help or stay late - and that sort of behaviour is now the norm rather than a rarity. It's becoming a risk for staff."
One department had lost 50 nurses out of 120 in the past two years - and more would leave now international borders were opening, she said.
Intensive care specialist Andrew Stapleton, who is based at Hutt Hospital, said GP clinics and emergency departments were bearing the brunt of the outbreak at present.
"We are alarmed by the rapid rise of case numbers and therefore by the hospital numbers that are rising a week or so later - and I suspect those numbers are rising more rapidly than the modelling suggested.
"So we wait nervously to see what happens - because there is always a lag between case numbers and hospitalisations, and another lag between hospitalisations and ICU."
As the pandemic surges, Stapleton fears the number needing hospital care could overwhelm the system at some point.
"Even if Omicron overall is not such a dangerous disease, other patients with other medical conditions are missing out because the hospital is so full of these other patients."
Chief medical officer for Capital and Coast and Hutt John Tait was not available for interview.
In a statement, he said some planned surgery and specialist appointments may need to be rescheduled.
"Rescheduling will only occur if clinically safe and appropriate, and in discussion with patients. We work very closely with the private sector, and will continue to do so."
RNZ asked how many operations had already been postponed but was told to put in an Official Information request.
As of midnight on Wednesday, there were just under 27,000 active Covid cases reported in the region - including 65 in hospital.
Modelling by Te Pūnaha Matatini shows the greater Wellington region is on track to hit between 40,000 and 55,000 cases by the end of April, with between 85 and 130 people in hospital at the peak.
The total number of infections will be higher, but not everyone will get tested.