Gastrointestinal illnesses and influenza are causing serious overcrowding in Montreal hospital emergency rooms.

The city's Health and Social Services Agency says it is quite concerned since half of Montreal hospitals are working at an average of 50 percent above their maximum capacity.

Across the island of Montreal, St. Mary's, the Verdun General and the Montreal General hospitals have the heaviest loads. St. Mary's is at 227 percent of capacity, Verdun General at 223 percent, and the Montreal General at double its maximum working load.

The only hospitals even approaching normal patient levels in their emergency rooms are the Montreal Children's and Hopital Saint-Luc, and even those ER departments are about 16 percent overcapacity.

ER overcrowding is normal during the Christmas and New Year's holiday season but the number of patients normally is reduced as doctors and nurses return to work.

However this year the situation is still serious, so much so that hospitals are being told they can postpone elective surgeries and cancel outpatient appointments in order to free up beds and staff.

Health and social services officials say there are signs things are improving.

"The number of ambulance [visits] is going down. We have had a very high level in the last six weeks," said Frederic Abergel.

"It's not a trend but in the last two days we've seen a decrease in the number of ambulances. If it goes on for more days we will be able to say that it's a trend."

Last year more patients showed up in the ER needing treatment under their own power, instead of taking an ambulance.

The agency doesn't know why that is.