Almost 400 people are waiting for a hospital bed in Northern Ireland, BBC News NI understands.
It is thought the majority of extra beds which are used in an emergency are already occupied.
Flu and respiratory infections are affecting many people with some requiring hospital treatment.
BBC News NI also understands that 41 ambulances are queued outside Northern Ireland’s emergency departments as of 15:00 GMT on Saturday.
One ambulance has been waiting outside a hospital for nine hours.
There is not enough staff or space to facilitate crews or patients.
One BBC reporter said at least seven ambulances were waiting to off-load patients at Causeway Hospital in Coleraine on Saturday afternoon.
The Western Trust said that as of Saturday afternoon, 70 people are awaiting beds across their trust area.
This number includes 22 people at the South West Acute Hospital in Enniskillen and 48 people waiting at Altnagelvin Hospital in Londonderry.
On Friday, the Belfast Health and Social Care Trust reported a total of 38 patients were waiting for admission to a hospital bed.
A spokesperson for the Belfast Trust told BBC News NI that this is a particularly busy time of year.
“When fewer people are in work, the numbers we see in emergency departments are exacerbated as they are more likely to come in for lesser injuries, which shows these increases in waiting period’s.”
BBC News NI has contacted each of Northern Ireland’s health and social care trusts for comment.
