The Mater hospital in Dublin has said its committee which decided to delay giving approval for clinical trials of a new cancer treatment will meet again in a number of weeks to reconsider the decision.
The decision to delay the trials was made by a hospital sub-group, not the hospital's ethics committee, a spokeswoman said.
The decision was made because of concerns that women availing of the treatment had to use contraception, which was against the hospital's ethos.
In a statement yesterday the Mater said: "The absolute requirement of some pharmaceutical companies that women of childbearing age must use contraceptives during trials is not supported by our ethos.
"The hospital believes that individuals and couples, following their own informed conscience and guided by medical advice, have the right to decide how they will go about avoiding pregnancy."
It added the hospital was redeveloping its existing consent procedures to ensure patients were fully informed of the issues.
The Mater's decision was criticised by consultant cancer specialist Dr John Crown, who said he believed there was "a fundamental tension and contradiction" in the owners of a hospital entirely funded by public money trying to impose their ethos on patients of all faiths and none.
Other hospitals have already given approval for the drug Tarceva, which is said to prolong life in patients with lung cancer, to be used in clinical trials. If women became pregnant while on the drug, the effect on their baby could be catastrophic.
Labour's health spokeswoman Liz McManus called on Minister for Health Mary Harney to intervene. "It is absolutely vital that women are given the best possible treatment for any form of cancer. All life-saving measures must be tested and it is bizarre that a trial that has already been approved by the Irish Medicines Board and the ethics committee at Tallaght hospital should be deferred by the Mater.
"In effect, the hospital's ethics committee is placing a veto on women's health," she said.
A source close to the clinical trials process said the Mater hospital had a habit of delaying clinical trials. While approval for trials could take eight weeks at Tallaght hospital, they could take six months at the Mater, he said.
The issue of hospital ethos affecting approval for clinical trials also arose at St Vincent's hospital more than a year ago, according to Dr Crown. He said the ethics committee at St Vincent's raised concerns about a trial for which he sought approval, again because women taking part would have to use contraception.
However, he said the trial went ahead after he raised concerns and demanded the discussion on it by the ethics committee be minuted. Dr Crown said that under an EU clinical trials directive, which came into effect in 2004, any doctor wanting to partake in a clinical trial can now obtain the approval of an ethics committee in any hospital in the State.
This approval can then be sent, along with a letter from the Irish Medicines Board approving the trial, to the ethics committee in the doctor's own hospital.
St Vincent's has, for example, gone ahead with clinical trials, despite its ethos, by getting approval for them from the ethics committee at Tallaght hospital.
It is understood approval had been sought from another Dublin hospital for the trial at the Mater when the ethics committee expressed concern.
The Department of Health said that despite the EU directive, a hospital ethics committee may decide on a case-by-case basis whether to permit a trial to be carried out at its hospital.
Ms Harney said she wouldn't want to interfere with the ethos of any institution. "That is a matter for the ethics committee in each individual hospital," she said, "but I have a supervisory role as Minister for Health and Children and recently we asked the Irish Council for Bioethics to give us advice in relation to guidelines for the conduct of clinical trials."