New Zealand's 20 district health boards are disappointed doctors are planing to strike for 48 hours.

After nine months of discussions about hours of work, 3200 doctors aligned with The New Zealand Resident Doctor's Association will walk off the job on October 18, including more than 480 doctors in Canterbury.

CDHB's People and Capability Manager, Michael Frampton, says anyone needing emergency or urgent care will still be able to receive it.

"The significant will be for people who are having planned operations, outpatient appointments and those kind of services."

Rachel Smalley: No-one should have to work 12 days in a row

Operations in Canterbury will be cancelled as well as hundreds of outpatient appointments.

"So this is a very significant disruption to the care people of Canterbury should be expecting from their health system, during that time," Mr Frampton said.

The union representing the striking staff says they're overworked - putting patients at risk.

In August, The Resident Doctors Association called for all 20 DHBs to adjust rosters to suit safer hours.

Mr Frampton says at the CDHB a majority of junior doctors would work 12 consecutive days around once every couple of months.

• Rachel Smalley: No-one should have to work 12 days in a row

"Now let's be really clear that the average junior doctor works around about 55 hours per week. The notion that junior doctors are working 80, 90, 100 hours a week is simply not true."