Nearly 75,000 people on the New Zealand Register of Nurses are certified to work, but many are avoiding the industry, according to the Nurses Organisation.

Nearly half the country’s nurses aren't working as nurses, according to recent reports, with some taking jobs in supermarkets or on road gangs as a preference to healthcare.

Te Whatu Ora is keen to persuade some back to the frontlines but one former nurse said returning to work in the health system would be like going back into an “abusive marriage”.

As Nurses Organisation kaiwhakahaere, Kerri Nuku told the Mike Hosking Breakfast the exact figures of registered nurses are kept secret by the Nursing Council, which makes nailing down exact numbers difficult. But she said some had moved to Australia for work.

Hosking asked why, when so many nurses were available and ready to work, there was still a serious workforce shortage.

Nuku said exit interviews with nurses leaving their posts had given clues: "They say they've given up in frustration because the system is overworking them, it's dangerous to work," she said.

According to Nuku, nurses will go to work to protect their nursing certificate, which allows them to work in the first place - but also to deliver safe and quality care to patients.

"Whenever that's compromised, the nurse becomes more pressured and makes the decision to leave, or it becomes attractive to go to another job without that same pressure or responsibility."

Nuki said nurses will make a heavy financial investment to become qualified, but the vocation can lead to nasty surprises.

"When you get out there and you're actually in the real workforce where the pressure is intense, you have to look at the fact the quality of life you thought you'd have is somewhat compromised," she said.

"It's hard to go home at the end of the shift and cut off; you're always thinking 'Have I done the right thing?' so that psychological pressure is intense, sometimes that's what is underestimated in the training."

The Government recently launched a major plan to plug forecast healthcare worker shortages of 13,000 nurses and more than 5000 doctors within a decade.

Overall, the health system has about 8000 vacancies and, based on current population growth, an extra 1600 workers will be needed every year until 2032, meaning if nothing changes the gap could grow to 25,000 healthcare professionals.

Initiatives include “earn-as-you-learn” programmes, targeted rural programmes and funding for 50 new medical school places.

It also included improved working conditions and support for healthcare workers, such as reintroducing free meals and a Health Workforce Wellbeing Hub, including an occupational health and wellbeing service.

Health Minister Ayesha Verrall has previously said while the extent of some of the gaps was “confronting” they had to know where they were so they could address them.

“This problem has been decades in the making. And we’ve heard from our health workforce, that they’re under pressure. So no, I’m not surprised," she said.