Twenty-one Wellington GPs employed by Te Rūnanga O Toa Rangatira are beginning a series of strikes on Friday.
They want dentists included in their agreement, but the iwi health provider that employs them says no.
It'll be the first time in New Zealand GPs have gone on strike. Junior doctors have taken industrial action in recent years over their difficult rosters.
Association of Salaried Medical Specialists (ASMS) spokesperson Lloyd Woods says the current arrangement is unfair.
"The point of principle here is dentists are part of the wider medical team, and their conditions of employment and what have you are a little bit secondary."
Te Rūnanga O Toa Rangatira says the agreement isn't tailored for dentists, so it would be inappropriate to include them.
Over the next couple of weeks five one-hour strikes will be held at five practices in Porirua and Newtown, before a full-day strike that's scheduled for December 24.
"Doctors won't be available for an hour for each of the five days... which means that basically fewer patients will be seen," said Mr Woods.
He said the strikes could have been avoided if dentists were allowed to join the collective agreement, which makes sense since they all work together and have "similar" levels of qualifications.
"They have said that the collective agreement was designed for doctors and would never cover dentists - and that is true, because we've never had any dentists to cover."
Dentists have been a part of the team since 2008, according to ASMS.
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A spokesperson for the Te Rūnanga O Toa Rangatira said they're still committed to reaching an agreement. ASMS said further industrial action is "almost certain" if the employer refuses to budge.