Some to state the impact include:
• Counties Manukau DHB - 600 appointments for elective surgery or an outpatient consultation,
• Waikato - 530 outpatient appointments and 98 inpatient appointments,
• Canterbury - Hundreds of outpatient appointments and around 150 elective surgeries.
National contingency planner for the DHBs, Anne Aitcheson, said national figures would not be collated until after the strike.
"In the past we have had patients on standby and clinics on standby that we have thought we have not been able to do and we have been able to provide services in addition during the strike.
"Everybody is very well prepared and very well planned so we would say the risk is minimal - but we do have a withdrawal of labour."
Hospitals were very busy over the weekend, some remaining at more than 100 per cent occupancy this morning.
"We would hope it would be lower than 80 per cent [tomorrow], but given how full some were this morning that may not be achieved."
"The main workforce is the senior medical staff. A lot of the work they would normally do they are not doing this week - elective work and a number of outpatient clinics - so they can be in the wards and in the emergency department . . . "
Auckland DHB would not say how many appointments had been postponed. It says patients who have follow-up appointments during the strike should attend as scheduled unless told otherwise by the DHB.
Counties Manukau said its ED would be fully staffed "and we will have the capacity to undertake all acute surgery and medical procedures".
"During the two days of the strike, if people experience a condition that is not urgent or severe, please contact Healthline on 0800 611 116 or their GP in the first instance.
"Patients whose appointments have been rescheduled have been contacted directly."
The senior doctors' union has advised members to claim extra pay of $340 an hour for work that becomes more onerous in the absence of normal resident doctor support, and $568 an hour for any additional work they do as a result of the strike.
The union was seeking the rates paid in the 2008 resident doctors' strike plus inflation.
The DHBs say they offered rates of from $180 to $500 an hour, and that some senior doctors had told of being "embarrassed by the 2008 rates".
Separately, more than 1000 ambulance officers at St John today issued a fortnight's notice of industrial action after what the First Union said was a bid by the employer "to squeeze more out of already stretched front-line staff". The action includes a ban on paperwork, disrupting St John's ability to invoice patients; ambulance officers will continue to respond to call-outs.
"We are seeking solutions to issues that cause dangerous fatigue such as not receiving rest and meal breaks coupled with an increased workload," said union official Lynette Blacklaws.
St John human resources director Tom Dodd said: "We are in the middle of collective bargaining with our five unions and had already agreed to mediation before this notification was issued. We continue to work in good faith and discuss relevant issues directly with unions and our staff."
The resident doctors' strike
• For 48 hours from 7am tomorrow
• Acute and emergency services are running as normal
• Many non-urgent hospital appointments are being deferred
• Some DHBs have said they want patients to arrive for appointments unless they have been told otherwise
• Contact your DHB or check its website if unsure
The dispute
The Resident Doctors Association has:
• Asked that rosters of seven nights in a row be replaced with a maximum of four nights in a row followed by three days off,
• Asked that 12 days in a row followed by two days off be changed to a maximum of 10 days in a row and four days off,
• Rejected the assertion it is seeking pay for extra days off.
The DHBs have:
• Agreed to split night shifts that the union reports cause fatigue,
• Given an assurance that the maximum number of days worked in a row will be reduced to 10 days,
• Refused what they say is an RDA claim for members to be paid for the days off that will result from the roster changes.
