After-hours medical services in some regions are on the verge of collapse, as overworked GPs signal they can no longer provide cover or the funding falls short.

Documents obtained under the Official Information Act show in the first eight months of last year, 24 practices and clinics had to reduce hours or close their doors due to critical staff shortages and cost pressures.

In Porirua, health officials are considering replacing the overnight doctor at Kenepuru Community Hospital's accident and medical centre with a telehealth service.

It is a 25km trip to Wellington Hospital - and about the same distance to Hutt Hospital - if you have a car.

Ngāti Toa chief executive Helmut Modlik says in Porirua the iwi-run health service Ora Toa and other clinics already cover Thursday nights and the weekends.

He's confident they can provide the doctors - if Te Whatu Ora paid them.

"It's just signalling to them and everybody else in our community that we just cannot accept that there will be a stepping back from making those services available."

The senior doctors union says staff are seeing more than 20 patients in a single night - including a small number of "high acuity" cases several times a week.

Executive director Sarah Dalton says it's a critical service for more than 100,000 people, and the same thing is happening in other regions.

"What is a reasonable level of public health provision, given that we know that people don't always get acutely unwell of deteriorate quickly between the hours of 8am and 5pm?"

In the 13 months to August, urgent care clinics in Auckland were forced to close early nearly 200 times due to staff shortages.

Nationwide there were more than 100 providers of after-hours care, each with a different mix of funding from Te Whatu Ora, primary health organisations, ACC, private providers and patient co-payments.

Te Whatu Ora has boosted annual funding by $17 million to "stabilise" urgent care services.

But GPs across the country say current funding ys not enough to cover the day-to-day work, let alone afterhours care.

The only on-call night time GP service between Whangārei and Auckland's North Shore closed in March.

General Practice New Zealand chair Porirua GP Bryan Betty says it's patients who end up paying the price.

"It does lead to problems in terms of late presentations and presentations to emergency departments which puts pressures on already overstretched services."

The not-for-profit organisation SouthLink Trust runs 23 practices nationwide.

Its chief executive, Karl Andrews, says the current regional variability of after-hours contracts has to be addressed with urgency.

The growing complexity of patients, increased administration and a shrinking workforce was making it harder to even provide day-to-day services, he says.

Te Whatu Ora says it's planning to look at urgent care as part of its wider primary care programme - but meanwhile, a range of telehealth services are available, and any patient in need of urgent treatment can always visit a hospital emergency department.

-RNZ.