Patients on Monday night were left facing delays of more than 10 hours to be seen at an under-strain Co Armagh emergency department.
SDLP councillor Declan McAlinden has described conditions in Craigavon Area Hospital, with ambulances queuing at the door, and patients facing waits of more than 10 hours.
A spokesperson for the Southern Health and Social Care Trust said attendances at the hospital's emergency department were "just above average" on Monday.
Speaking to the Belfast Telegraph, he said he attended the hospital after receiving a call at about 10.30pm from a member of staff who said the situation was the worst they had seen in 20 years.
"I went inside for a look around, in the main waiting area, there was maybe 50 or 60 waiting to be called," he said.
"I also went into the hallways, and there were patients with breathing apparatuses and also young kids with masks on their faces.
"It was quite distressing to see how bad it was."
Mr McAlinden said he spoke to one elderly woman who had travelled from the village of Pomeroy in Co Tyrone, and had been waiting since midday.
She was still there at 11pm in the evening, and estimated it would be another hour before she had an x-ray taken.
He said another woman who had travelled from Cookstown in Co Tyrone had experienced a similar wait.
"I have to say this, the staff were absolutely fantastic. I can do nothing but praise the staff and the conditions they are working under," he added.
A spokeswoman for the Southern Health and Social Care Trust said it apologised to patients facing excessive waits, and said Monday is one of its busiest days.
"Attendances at Craigavon Area Hospital ED on Monday were just above average, and there were high numbers of sick patients requiring admission to hospital beds. 72 ambulances arrived at Craigavon’s ED on Monday, which is not unexpected at this time of year," she said.
"There was a ‘spike’ in activity in the ED in the early evening period and this made the ED busier for a time, which is quite normal for an Emergency Department.
"Some patients did experience lengthy waiting times because of the high demand for beds across the hospital and we apologise to them for having to wait longer."