Resident doctors across the Waikato have walked off the job as part of a 73-hour strike which began this morning.

But the Waikato District Health Board says the Thames Hospital will be mostly unaffected by the three-day strike which started at 7am and runs up until 8am on Friday, January 20.

Due to the strike, the Waikato DHB has been forced to postpone and reschedule about 500 outpatient and mental health clinics, and non-emergency surgeries.

All patients whose appointments have been affected by the strike should have been notified by telephone or mail. However, not all clinics are being rescheduled so the board is asking patients who've not been notified to please attend for their appointment.

Waikato DHB employs 420 resident doctors who mostly work out of Waikato Hospital, with about 70 per cent of these members of New Zealand Resident Doctors Association which has organised this latest strike.

The NZRDA says some resident doctors are made to work unsafe hours 12 days in a row, and night shifts of seven days in a row. It is seeking a maximum of four nights in a row followed by three days off and a maximum 10 days in a row with four days off.

Waikato DHB Acting Chief Medical Officer Dr Doug Stephenson also wants to remind members of the community that while the strike takes place to please keep emergency department for emergencies only.

Patients can also contact Healthline for advice on 0800 611 611 or visit the new free online out of hours doctor service at www.smarthealth.org.nz

For all emergencies call 111.

For people who are unsure about their appointment are being asked to call the DHB's free helpline on 0800 276 216.

For more updates on the strike visit the Waikato District Health Board's website at www.waikatodhb.health.nz/strike