“Significant” IT issues at services across the Southern Health Trust will continue into Thursday with the majority of planned surgery and out-patient hospital appointments being cancelled.

A major incident is still ongoing at sites, including Craigavon and Daisy Hill hospitals, as ambulances are being diverted while work continues to resolve the problems, the trust said.

The Department of Health said the cause of the issues is currently unknown and an “urgent investigation” is under way to try and restore services as soon as possible.

Patients were warned not to come to appointments at any hospital or community service in the trust’s area on Wednesday.

Priority is being given to emergency and critically ill patients.

In a statement the trust said planned surgery and out-patient hospital appointments will be rescheduled as soon as possible.

One patient at Daisy Hill hospital said she is “devastated” that she can not get an operation she has been waiting nearly a year for.

Elaine Agnew’s operation was planned for Wednesday and she has been waiting since November.

She told BBC News NI she has no idea when it will be rescheduled.

Mrs Agnew said she’s “devastated” but asked: “What can I do?”

She added that despite the disruption staff at the hospital have been “brilliant”.

Nicola Burns was taking her son Lorcán to Daisy Hill to get a cast removed after falling off his bike.

“We had an appointment for an x-ray in the fracture clinic, turned up here and told it’s been cancelled, bit disappointing to get him out of school, now we have to home again,” she said.

Ms Burns said they had “no idea of the problem” until they were there.

“We kind of knew straight away, the waiting room was empty. It’s a hassle he’s got out of school, and I’ve left work.”

She added: “We were hoping he was going to get word of getting it off, now we don’t know. We’ve to come back next week.”

However, Lorcán said: “I don’t mind”.

He has been wearing the cast for four weeks.

Gerard Lennon was told he cannot leave Daisy Hill until he gets the results of a blood test, which have been delayed by the IT issues.

He said he has not been told how long he will have to wait.

“I know I’m probably in for a long wait but I don’t mind.

“It was either here or Dundonald and there were 140 people waiting when I was there this morning.”

The Southern Health Trust covers a number of hospitals and care centres across counties Tyrone, Armagh and Down.

It includes South Tyrone Hospital in Dungannon, Craigavon Area Hospital, Lurgan Hospital, St Luke’s Hospital in Armagh and Daisy Hill Hospital in Newry.

The trust told BBC News NI the issue will run into Thursday, while the vast majority of community services and mental health domiciliary care will operate as normal.

However acute sites will be affected with outpatient and planned surgery having to be cancelled and rescheduled.

People have also been asked to avoid coming to its hospitals and other sites, but patient visiting is still possible.

The British Medical Association’s Northern Ireland Council deputy chair, Dr Clodagh Corrigan said: “Today’s events will inevitably impact waiting lists and is yet another clear indication of the dire need for investment.”

She said staff are “trying their best” to deliver safe and effective care in “circumstances entirely outside of their control”.

Sinn Féin MLA Linda Dillon said the IT problem was causing “significant disruption” to health services.

“I urge local people to monitor the Southern Trust’s social media and the news for updates as this situation unfolds,” she added.

Diane Dodds from the Democratic Unionist Party (DUP) sits on Stormont’s health committee and said the issue had put extra pressure on the whole health service.

“Ambulances that would normally be here bringing patients here are being diverted to other EDs that are already under significant pressure,” she said.

“We need to get the problem identified, sorted out and we need to make sure that the system that we’re operating within is much more resilient than it has proved to be thus far.”

Dodds added the cancellations were “bitterly disappointing” for patients who had been waiting a long time to receive treament.

“I will be pressing the trust to have these appointments and operations rescheduled as quickly as possible,” she added.

SDLP MLA Justin McNulty said there was “real worry and distress” for a large number of patients.

“It’s important that we work to understand how this has happened and ensure systems are put in place to prevent a repeat in future,” he said.

The deputy leader of the Alliance Party, Eóin Tennyson said his thoughts are with “patients, families, and staff who are under enormous pressure”.

He claimed: “Alliance will be seeking assurances that everything possible is being done to restore systems quickly, protect patient safety, and prevent similar failures in future.”