GWENT ambulance crews have had to wait more than an hour to transfer patients in to hospitals more than 7,000 times since 2010.

Figures from the Welsh Ambulance Trust reveal patients at Nevill Hall and the Royal Gwent hospitals waited between one and ten hours on 7,659 occasions in 2010/11 and 2011/12.

A total of 6,153 delays were for a period of between one and two hours, but in 107 incidents patients had to wait more than four hours to transfer to hospital.

The trust said possible reasons for the delays included no available trolley or chair, no bed available and no available nurse or medical staff.

Plaid Cymru, which obtained the figures under the Freedom of Information Act, say every minute ambulance crews spend off the road hits their ability to respond to emergency calls.

Gwent Plaid AM Jocelyn Davies said: "The ambulance service is on the frontline and is perhaps the most visible part of the NHS and is under constant scrutiny.

"But these figures reveal that much of the challenge they face is out of their hands. "How can they be as efficient as possible when there is a shortage of beds in hospitals or a lack of trolleys and they are having to stay with patients?"

She said the Welsh Government had some "explaining to do," claiming former health minister Lesley Griffiths had supplied figures that varied from those from the Welsh Ambulance Service.

Ms Griffiths had told the Assembly in February that between July 2012 and February 15 the average patient wait was 22 to 23 minutes and 60 per cent were handed over within the 15 minutes target.

A spokeswoman with the Aneurin Bevan Health Board said: "Ensuring patients in greatest clinical need receive the appropriate treatment and care is always our first priority and we apologise for any delay during exceptionally busy periods.

"Additional resources have been provided to our emergency care departments to create more capacity and therefore help release ambulance crews as soon as possible."