Patients needing urgent brain surgery are reportedly being turned away from Beaumont Hospital in Dublin.

The national neurosurgical centre had no beds for nine patients with malignant brain tumours last Friday, The Irish Times has reported.

The paper says it has seen an internal memo to the head of the unit, Dr Mohsen Javadpour, who suggests that patients are deteriorating at home while waiting for treatment.

The situation has been heavily criticised by opposition politicians.

Fianna Fáil health spokesperson, Billy Kelleher, said the situation at the hospital is "really worrying".

Speaking to Newstalk Breakfast, he said: "Regardless of ideological view, you can't have a situation where people are waiting inordinate length of times for very serious surgeries for brain aneurysms and brain tumours.

"The idea that a person with a malignant tumour [had an] operation cancelled because of staff shortages or theatre closures is unacceptable," he argued.

Sinn Féin health spokesperson Louise O'Reilly, meanwhile, believes that the revelations are only "one symptom of a broken system, that is replicated right across our [health] services".

"At the same time that there are no beds for these patients, the fact remains that many patients urgently requiring neuro-rehabilitation services are waiting in a hospital bed, simply because the rehabilitation services and teams are not in place," she said.

"These patients are waiting up to two years for rehab and as a result this places unnecessary pressures on acute hospitals."

She added that delays for critical surgeries are putting lives at risk:

Martin Varley of the Irish Hospital Consultants Association said it has highlighted the issue of overcrowding in acute hospitals in repeated pre-budget submissions. 

"The reductions in capital expenditure are exacerbating the problem. Over the past seven years, capital funding for acute hospitals has been cut by in excess of €500 million," he told Newstalk.com.

Beaumont Hospital said in a statement that "every effort" is being made to admit patients "based on clinical need". 

"The neurosurgery unit operates at close to 100% capacity and on average, the unit admits some 200 patients each month," it said.

"Delays in returning patients back to referring units can also contribute to capacity constraints in Beaumont.

"Today, there are currently six patients identified as requiring transfer to Beaumont neurosurgical department.  Of these, four will transfer today and two will transfer tomorrow."

It comes as figures show more than 6,000 people were left on trolleys in hospitals around the country last month.