The Health Minister Leo Varadkar says it is not just capacity that gives rise to over-crowding in emergency departments.

Hospital consultants are meeting with Mr Varadkar today to discuss the over-crowding crisis.

It emerged last week that a 91-year-old man was left on a trolley for 29 hours at Tallaght Hospital, and a 93-year-old woman had the same wait on a trolley at Beaumont Hospital.

Nurses will be balloted on industrial action over the issue today, and may strike in the run up to Christmas.

The Irish Hospital Consultants Association (IHCA) will meet Minister Varadkar later.

How to alleviate overcrowding on hospital trolleys will be top of the agenda.

But Minister Varadkar says additional beds do not necessarily mean less over-crowding.

2015 is on-track to produce a record high number of people on trolleys - and several groups have expressed deep concern as we approach winter.

IHCA president, Dr Gerard Crotty, says there are some extra beds on the way - but not enough.

"It's all too little, too late - the amount of efforts and capacity that's been provided is really a very small proportion of the total" he told Newstalk Breakfast.

"Demand is going up by 3% every year due to an ageing population and an increasing population".

"So we're really behind the curb and we're trying to catch up - and there needs to be a substantial change so that we can get ahead of the curb" he added.