The national gas network will not be extended to Sligo and the north-west from Galway without "significant" State aid, Bord Gβis's chief executive has said.

Mr Gerry Walsh said the prospect of such an extension was "in the lap of the gods" because the headage per pipeline was not sufficient to justify the investment.

"It's a big downer from an economic point of view," he said at a meeting of the Industry and Commerce Committee at the Royal Dublin Society.

"My view is that it won't happen without some sort of significant State support."

Groups in the north-west have expressed concern that they will not benefit from gas sourced in the Corrib field off the Co Mayo coast because the region is not on the national network.

While the Government has decided to extend the network to Sligo, Mr Walsh's comments leave no doubt that Bord Gβis is not willing to pay for the project.

The company is building a Dublin-Cork loop line via Galway and Limerick.

It is also building a link between Pollathomas, Co Mayo, and Galway - through which Corrib gas will be fed into the national system.

While the cost of the western link was projected at £220 million (€279 million), it is understood an additional £50 million has been added to costs because of construction price inflation.

This will have to be funded from within the State company.

Mr Walsh said the company's large infrastructure projects should proceed even if the economic slowdown continued.