About 500 ISS Mediclean workers, who also include telephonists, had threatened to start the action on Monday.

The strike action has been postponed for one week to allow some breathing space in the negotiations to discuss the latest offer

Unison spokesman

The strike would have severely disrupted Swansea's Singleton and Morriston hospitals.

The staff say they are unhappy because they receive less than their counterparts who work for the NHS and want their pay increased.

The hospitals have already been hit by a one-day strike in September and a two-day stoppage earlier this month.

ISS Mediclean has offered its staff a pay increase of 12%.

A spokesman for the public services union Unison said: "The strike action has been postponed for one week to allow some breathing space in the negotiations to discuss the latest offer.

"We still have to work on the finer details but, if the agreement is finalised, it is a significant step towards more equal pay in the Swansea NHS Trust."

The offer would see a domestic worker's salary increasing to �4.62 an hour and a porter's weekly wage rising to �5.14.

Porters have been offered a pay rise

The spokesman said this would be a significant increase for lower-paid workers.

"It means they can no longer be targets for loan sharks, and can at least survive," he said.

ISS Mediclean said it would continue to hold further discussions with its staff.

A company spokesman said the delay to the strike action was good news.

"We consider our pay offer to be generous and hope this signals an end to the disruption," he said.

Resolution

Swansea NHS Trust has welcomed the decision to postpone the action.

Director of Corporate Development Andrew Bellamy said: "We hope the dispute can be resolved without any further disruption."

ISS Mediclean is one of the world's largest facilities services providers.

The Dutch company employs 265,000 people in 38 countries.