Drawn out contract negotiations have some junior doctors calling for strike action, the New Zealand Resident Doctors' Association claims.

The public health system could face major disruption amid concerns that junior doctors could walk off the job over hours.

While a group representing New Zealand's district health boards (DHBs) is due to make a fresh offer to the union representing junior doctors this week, the New Zealand Resident Doctors' Association (NZRDA) is understood to be polling its members on their willingness to take industrial action.

The district health boards are aware of the poll, with a belief they could be issued with a notice of strike action before the end of September, a person linked to the negotiations said.

Dr Deborah Powell, national secretary of the NZRDA said members were not being formally balloted over strike action, but she did not deny that polling of members on the issue was underway.

"We're in the middle of MECA [multi employer collective agreement] dispute. We're getting input from our members constantly," Powell said.

"It would be fair to say that the level of frustration among the RMOs (resident medical officers) is getting very high and yes, we are getting calls to move to strike action."

The employers - representatives of New Zealand's DHBs - had promised to come back to the union by the end of this week "and until they have we're not going to be doing anything further," Powell said, however members were indicating a willingness for industrial action.

"Things are getting tense."

DHB shared services spokesman Mick Prior confirmed the DHBs would present a new offer to the union on Friday, but that it was not a final offer.

"It's not 'boom, take it or leave it, this is where the settlement lies'," Prior said.

"We'd hope they'd take that back to their members and have a sensible discussion with them."

The central issue keeping the two sides from agreement was over the hours the doctors were required to work, Prior said, claiming that the hours required of junior doctors in New Zealand were "probably quite good" compared to those faced by colleagues in other countries.

While the DHBs were willing to look at any particular roster the union had raised as a problem, it was not prepared to accede to the union's proposal for national solution, Prior said, claiming the union's stance was one of "intransigence".

"The union's got one single solution that they want, one particular roster for all RMOs at all levels, and all levels of training, which we don't think's right. We think that patient care and services and training should be the consideration first."

Prior declined to give details of the offer which would be tabled ahead of the meeting with the union.

"It would be inappropriate to cave to the demand."

The union had not raised the prospect of strike action in negotiations, however only it coukd say whether it was likely to happen, Prior said.

"It's a union prerogative, not ours, The DHBs have put a fair and reasonable offer to them," he said.

"We'd be disappointed if we got notice [of strike action] next week, not surprised."

A spokeswoman for Health Minister Jonathan Coleman said he could not comment "as it is an employment issue between the doctors and the DHBs".

For much of 2016 Britain's National Health Service has been struck by a series of strikes by junior doctors over proposals to overhaul existing contracts, including proposals to offer more services on weekends.