Te Whatu Ora is asking the Employment Relations Authority to step in and help resolve its pay dispute with senior doctors and dentists.

More than 5000 members of the Association of Salaried Medical Specialists are set to walk of the job for the third time on Thursday after last ditch talks on Tuesday ended in an impasse.

Te Whatu Ora chief executive Margie Apa says the agency has urged the union to join it in applying to the ERA for facilitated bargaining.

"We are disappointed that ASMS did not join us in this initiative but remain committed to doing all we can to resolve this dispute.

"We continue to urge the union executive to formally present the current offer to their membership."

The union says there has been no movement from Te Whatu Ora on its salary claim since it previously took the offer to members.

Its spokesperson says the offer on the table fails to even match inflation, and amounts to a pay cut for senior doctors and dentists for the third year in a row.

"Hospitals are currently short more than 1700 senior doctors and specialists (about 20-25 per cent) with that work being performed by the current staff.

"This is contributing to burnout and exasperating doctors wanting to leave the public system for private practice or overseas.

"Increasing the salary levels to not have them effectively go backwards will assist in the recruitment and retention of senior medical specialists."

Te Whatu Ora says its teams are still determining the impact of the strike, but it's likely up to 250 operations, procedures and specialist appointments would be deferred.

Meanwhile, senior doctors and dentists from Auckland hospitals are using their four-hour strike on Thursday to fundraise for Lifeline.

Staff from Auckland, Starship, Waitākere, North Shore, Greenlane and Middlemore hospitals along with community mental health will gather at Pukekawa / Auckland Domain at 11am.

The union will also make a donation to Lifeline in recognition of Mental Health Awareness Week.

- RNZ.