Shirley Bassey performed at Llangollen in July 2003

The canvas-roofed Royal Pavilion's main event is its annual eisteddfod, but organisers want to use its 4,000 capacity even further.

Eisteddfod chief executive Gwyn L Williams said it could be made into an enclosure suitable for all weathers.

A feasibility study is being carried out into the cost of the project.

Mr Williams suggested that developing the 13-year-old building could cost up to �15m, but he believed there would be a cheaper alternative.

It's very important that Shirley Bassey could come to us in December and January, not just July Gwyn L Williams

"If you're developing it in bricks and mortar and slate and glass like a gothic cathedral which is going to stand for a thousand years or more then probably [it would cost] �10 - 15m," he said.

"However, I will be very keen for it to be an imaginative, low-cost building made out of the newest 21st Century fabrics.

"The building is a fabulous iconic building and people recognise it the world over.

"If it became a commercial building with a square roof it would cease to have that kind of status."

The pavilion was used "for a couple of months a year" and its full potential had not been fulfilled, he said.

The Royal Pavilion was built in 1992

"It needs to be a facility we can use year round," Mr Williams said.

"It's very important that Shirley Bassey could come to us in December and January, not just July.

"I've no doubt that if we had a solid floor and if we had a waterproof and windproof enclosure we could hold a series of concerts and the venue could become a feature on rock and pop tours.

"At the moment we have rock and pop groups coming on an ad hoc basis but there have been so many approaches that I'm sure we could become part of the touring scene."

Established in 1947, the musical eisteddfod is one of the highlights of the Welsh cultural calendar.

Mr Williams announced his plan on Thursday during the unveiling of Llangollen Partnership, a new group set up to promote the town.

Organisers, including the county and local council, the tourism association and Llangollen's chamber of trade and commerce want to develop the town into an area like Keswick in the Lake District or Buxton in Derbyshire.

Members of Llangollen Partnership also want to improve parking in the town, develop tourism, and develop a secondary industry.