The drug's contents were not verified beforehand.

The decision came after dozens of anxious mothers sought help within hours of the disclosure of the mistake - although the authority said it had decided not to contact affected women to avoid alarming them.

Authority chief pharmacist Lee Pak-wai insisted yesterday there had been no problem with the procedure.

'And there was nothing wrong with the actual carrying-out of the dispensing,' he added.

'The pharmacist did check the label. But because there was no mention of preservative, there was an assumption that there was no preservative.

'In future we will insist our staff double-check and contact the manufacturers. We are going to review whether we can improve information coming from the manufacturers.' An authority hotline received 55 calls yesterday morning from worried women in its first four hours of operation.

The service will resume tomorrow.

'Fewer than half of the callers were on the list of affected women,' a spokesman said.

'Our senior nurses assured them that there are no side-effects and they should not panic. A few of them demanded medical check-ups. The Tsan Yuk hospital will arrange them soon.' Provisional Urban Councillor and Tsan Yuk Hospital Governing committee member Dominic Chan Choi-hi complained that the mistake had been covered up.

'I only got to know about this by reading the newspaper, although I am a member of the hospital's governing committee.

'I have complained to the hospital and demanded it contact all the affected mothers for medical check-ups,' Mr Chan said.