The trust said there was adequate cover this weekend

One staff member, who did not want to be identified, alleged that shifts were not being filled at some stations.

But the Welsh Ambulance Trust said it had ensured enough staff were on duty.

A spokeswoman said there was adequate cover and they planned to be flexible to changes in demand, which had "public safety as a priority."

Trust chief executive Anton Van Dellen admitted that a handful of stations out of 97 in Wales may have single crews on but denied any had shut.

He said he had authorised every shift in Wales, except one car shift, to be covered this weekend.

He told BBC Wales that this situation was not unusual and he had personally seen that there was adequate cover in the area so that patients would not be at risk.

He said that the problems stemmed from the fact that ambulance personnel hours had dropped from 42 hours a week to 37.5 hours and filling shifts was difficult at weekends.

As far we're concerned we have authorised sufficient resources to provide the level of cover that is needed this weekend Welsh Ambulance Trust spokeswoman

The trust said it had been actively looking for staff cover and denied claims there was an overtime ban in place.

"If someone is saying there is only one person on the ambulance station, it is not because we haven't asked for cover to be provided," said a trust spokeswoman.

"There isn't an overtime ban. We plan cover in accordance with the deployment plan.

"That plan has public safety as a priority. It has to be flexible to respond to changes in demand and resources are brought in as required.

Adequate cover

"As far we're concerned we have authorised sufficient resources to provide the level of cover that is needed this weekend".

One staff member claimed that several ambulance stations were affected by low staffing levels on Saturday.

It follows the release of papers to the BBC which suggested three out of five ambulance stations in mid Wales would be closed this weekend.

But on Saturday, the trust said it had authorised two crew members for every ambulance station this weekend and that there was "adequate cover" in all stations, unless something unforeseeable, such as an employee falling ill had occurred.

On Tuesday. the Trust board will meet to discuss implementing more flexible cover in south east Wales.