A junior doctors' strike is only going ahead because district health board chief executives could not get their act together to sign off on an agreement, a junior doctor says.

Photo: RNZ / Andrew Collins

The Resident Doctors' Association will go ahead with a three-day strike over rosters and pay from next Tuesday, affecting 18 of 20 DHBs.

It is the second round of industrial action by the union, after a two-day strike in October.

The Taranaki and West Coast DHBs are not taking part.

District health boards have accused the union of ignoring the impact a strike could have on patients.

Lead chief executive for the DHBs, Julie Patterson, said more than 2200 patients will be affected by the strike.

Waikato DHB had already postponed 500 patient bookings, along with 350 at Bay of Plenty DHB, she said.

However, one of the junior doctors' negotiators, Sam Holford, said the strike was only happening because the DHBs couldn't get their act together to ratify an agreement.

"We actually have what's very close to being a done deal on the table, but the reason we have to strike is that the CEOs won't meet wiht us and they won't meet with each other, to actually confirm or make an offer."

Ms Patterson said the DHBs' negotiators have gone as far as they can, and will present terms to health board representatives next Thursday.

The strike was "heart-breaking" for other DHB staff, who had to tell patients that their treatments would be rescheduled, including a woman with breast cancer who was told her mastectomy would be postponed for a few weeks, Mrs Patterson said.