The Department of Health says it will make a statement on the admissions crisis in hospitals - but not until tomorrow.

The Department has said the Health Minister is out of the country but is being kept up to date with the overcrowding crisis in our hospitals.

As the number of people on trolleys and chairs in Emergency Departments reached over 600 today opposition parties have criticised the lack of a statement from Leo Varadkar.

Members of the Irish Nurses and Midwives Organisation are to ballot on industrial action over the crisis.

A statement from the Department of Health this evening says the Minister is due back at his desk tomorrow but has kept in close contact, including having regular discussions with senior HSE management.

Opposition politicians have been questioning the whereabouts of Varadkar, with Sinn Féin President Gerry Adams saying the Health Minister had "gone AWOL". Fiann Fáil health spokesperson Billy Kelleher has said "it is time for the government to act" and that Mr Varadkar needs to publicly comment on the situation.

“Hospital overcrowding is now a major crisis facing the State. There are more than 600 patients on trolleys," Mr Adams said.

“Meanwhile the Minister for Health appears to be AWOL. This is unacceptable. Minister Varadkar needs to surface and to address this developing crisis with urgency."

“The HSE have now said themselves that patient safety is being compromised, so when the organisation that is charged with providing the service is saying that patient safety is compromised well then the government has to respond to that,” Mr Kelleher said said.

“It’s time for the Minister to act and we would like to hear a statement about what he intends to do with the hands on approach that he has claimed to have as the minister for health,” he added.

According to the Irish Nurses and Midwives Organisations (INMO) 601 people are now waiting for hospital beds.

The Health Service Executive (HSE) says the spike in overcrowding is largely down to delays in discharging older patients to appropriate settings. It points out that €25m has been provided for delayed discharge patients this year.

However, the INMO says the overcrowding situation is only going to get worse.

It is demanding more nurses and more open beds - and wants all non-emergency admissions to be postponed for at least a fortnight.

It follows the resignation of the HSE director of acute hospitals - who is also charged with reducing overcrowding in emergency departments.

In a statement last night, the HSE said Dr Tony O'Connell is returning to his native Australia, where his wife is taking up an academic position.

The Jobs Minister Richard Bruton had earlier said he would not be commenting on the whereabouts of the health minister.

Mr Bruton says there is no overnight fix to the problem.