Roche has stopped delivering drugs to some state-funded hospitals in Greece which have not paid their bills, the Swiss major's chief executive has told the Wall Street Journal.

Severin Schwan told the newspaper that patients have not been deprived of their treatments as a result of the new measures but some must take their prescriptions to a local pharmacy, and, in the case of intravenous or injected cancer drugs, bring them back to the hospital to be administered.

There are hospitals "who haven't paid their bills in three or four years," he added and "there comes a point where the business is not sustainable anymore".

Mr Schwan went on to say Roche may need to adopt similar measures in Spain, as well, while some state-funded hospitals in Portugal and Italy have also fallen far behind on payments.

Greek hospitals have large debts to a number of drugmakers, according to a recent report from the Hellenic Association of Pharmaceutical Companies (SFEE) cited by the WSJ. Its state-financed hospitals had paid for just 37% of the 1.9 billion euros worth of drugs delivered by SFEE member companies in the 18 months to June 2011.

Early this year, Greece tried to clear some debts by issuing pharma companies with bonds. "We didn't have a choice. Everybody got government bonds. The question was, you got nothing or you got government bonds," Mr Schwan told the WSJ, adding that Roche sold them immediately.