The trusts' merger will happen in April 2008

Pembrokeshire and Derwen, Ceredigion and Mid Wales and Carmarthenshire NHS Trusts will merge on 1 April.

Meanwhile, Ms Hart has also agreed to the merger of Swansea and Bro Morgannwg NHS trusts.

Ceredigion Community Health Council had opposed the move in mid and south west and feared services would be affected.

Keith Thomson who led the merger team in Pembrokeshire, Carmarthenshire and Ceredigion, said one trust would lead to improved services.

But Monica Williams, chief officer of Ceredigion Community Health Council, said she was "disappointed" by the minister's decision, but not surprised.

Paul Williams, who worked on the merger of Swansea and Bro Morgannwg NHS trusts, said his team welcomed the opportunity to "create a strong, innovative trust."