Patients were treated in the car park of the largest hospital in Co Antrim yesterday because of the pressure of the pandemic.
The Antrim Area Hospital and the neighbouring Causeway hospital in Coleraine treated a record number of in-patients with Covid-19 in the last 24 hours.
Yesterday the Northern Trust hospital group had admitted a record 126 patients with Covid-19 -- filling a quarter of the beds in its two acute hospitals.
96 of them were at the Antrim Area Hospital.
But another 43 people were waiting to be admitted after turning up to the casualty department.
They all had to be tested for Covid-19 so that they could be sent to the Covid or non-Covid area of the hospital.
And as the pressure mounted throughout the day, ambulances started to build up outside.
That peaked at 4pm when 17 were parked up with their engines running
Inside were patients who'd got as far as the hospital, but couldn't be brought in.
In a statement, a spokesman for the hospital group said: "That is not a satisfactory situation in anybody's book."
486 more people tested positive in Northern Ireland in the latest official statistics, and six more patients have died.
The Northern Executive is set to discuss stronger restrictions on Thursday.