The Taoiseach has defended the Government's record on patient safety following a warning from four hospital chief executives that cutbacks were affecting patient services.

Enda Kenny told the Dáil that it has been a very challenging year for the health service.

However, he rejected Opposition claims that patient safety was not a priority for the Government.

Yesterday, it emerged the chief executives of four of Ireland's largest hospitals wrote to HSE Director General Tony O'Brien warning that cuts in funding, coupled with accelerated demand for patient services, have begun to seriously threaten the quality and safety of patient services.

The letter was sent by the chief executives of St James's Hospital, the Mater Hospital, Tallaght Hospital and Our Lady's Children's Hospital, Crumlin.

The chief executives state that it is inherently contradictory to ask hospitals to reduce waiting lists and staff numbers, while at the same time guaranteeing safe services to patients.

An oncologist at Our Lady's Children's Hospital, Crumlin has said a number of cancer patients at the hospital have experienced delays in the delivery of chemotherapy.

Consultant oncologist Owen Smith said children and teenagers with cancer were experiencing delays of up to four days in receiving treatment.

Speaking on RTÉ's Morning Ireland, Dr Smith said: "A lot of our cancers in children are high-grade malignancies and we really need to get these drugs into these children in a scheduled, timely fashion. 

"Failure to do that will have knock-on effects in terms of survival."

He said delays at the children's hospital were having a direct effect on patients and adding to the anxiety of parents.

"We cannot continue to give the quality of care we have been giving to these patients with the current resources. It's not feasible anymore," Dr Smith said.

Consultant oncologist and Senator John Crown has said the fact that four hospital chief executives have written to Mr O'Brien over funding cuts indicates there are real problems occurring in the health service.

He said it was extraordinary that four people, whose career progression generally is in the gift of those to whom they are making the complaints, are now making this point.

Prof Crown said the significance is that this warning is coming from a group who do not normally point out service deficiencies, but who tend to defend the system when doctors and nurses point out deficiencies.

The National Association of GPs said it supports the four hospital chief executives in the position they have taken.

The association said it was not possible to reduce funding to hospitals and general practice and at the same time maintain services and patient safety.

It said that one of the factors contributing to the 10% increase in attendances at emergency departments over the last two years is cuts to primary care.

Meanwhile, Connolly Hospital Blanchardstown in Dublin has said it is under severe pressure to break even this year and has asked staff to "optimise the private occupancy"  between now and the end of the year to generate money.

In a memo issued to all clinical nurse managers and nursing staff on 29 October, the hospital states that it has also capped the number of healthcare assistants at seven each day for the entire hospital, until the end of the year.

Daily reports will be monitored by the hospital management team on the number of private patients being admitted.

Family members are also being asked to accompany relatives on escorts where it is feasible and safe to do so, to free up staff.

The hospital said a directive in the memo to reduce agency staff and overtime has not yet been implemented.

The memo was issued by acting Director of Nursing Anne Murphy.