The head of the South Eastern Health Trust has called for a resurrection of Stormont to tackle demands for pay parity.
Seamus McGoran was speaking as thousands of nurses took part in their second day of strikes over pay and staffing levels.
They are demanding equal pay for equal work after pay parity between Northern Ireland and the rest of the UK ended in 2014.
Another strike is due to take place on Friday where RCN and UNISON health workers will take action.
He told the PA news agency that 712 outpatient appointments and 155 procedures had been cancelled across trust sites, which include the Ulster and Lagan Valley Hospitals.
The senior official added the true impact is higher, revealing there are usually 1,600 outpatient appointments on a typical Wednesday but they stopped booking slots when they learned of the planned industrial action.
"There is quite a significant impact across our hospital services. There will be further impact with cancellations on Friday, albeit to a lesser extent, 340 outpatients and 89 procedures - but I don't underestimate on an individual personal level what that means for all of those people," he said.
Mr McGoran said he is content the trust has "managed things as best we can on a difficult day".
"But we are feeling real pressure now at the Ulster Hospital emergency department as we expected," he said.
Mr McGoran said he wanted to make it clear on behalf of the chief executives of all the health trusts in Northern Ireland that they support their staff and what he termed "their legitimate claim for pay parity with their colleagues in England".
"They are incredible people, they do a fantastic job for our patients and we believe they should be rewarded in the same way as colleagues are in other parts of the UK," he said.
"We obviously recognise the authority is not within the gift of our department of health and we are very clear that we need a political solution to actually deal with this as a matter of urgency.
"We are really, really hoping that our politicians can get their act together and find an agreement to get back into an executive before January 13.
"That's really where we need to see a solution."
Mr McGoran said the health service needs political leadership.
"I think when it comes to staffing levels for our services, ourselves, our staff, our trade union colleagues, we're all on the same page with this, we all recognise the huge, ever-increasing demand on our services and all want to build our staffing levels up to the point where we have absolute ability to meet all of the needs of our patients," he said.
"We're having to prioritise our most urgent patients and, for example, those who are waiting for planned care, those numbers are getting bigger and the lengths of waits is getting longer, so we really need political leadership.
"We need long-term investment and we need a workforce plan that will deliver more sustainable staffing levels for many years to come."
Midwives in Northern Ireland are now being balloted on whether to take industrial action over pay.
Voting opened on Monday and will close on 29 January.
The union representing midwives said they are also paid less than their counterparts in England, Scotland and Wales.
Additional reporting Gail Conway