The survey of US firms, presented by Indecon to the American Chamber on Friday, revealed that 43.5% of firms were considering moving part of their businesses from Ireland.

In an unreleased copy of his remarks obtained by the managing director Alan Gray told the American Chamber that his report should not be cause for panic, however.

"Structural adjustments, " said Gray, were part of "the ongoing and appropriate review of finding the best location for specific types of activities. . . the challenge for policymakers is to find replacement activities from other firms for any parts of Irish operations which are relocated."

He stressed that the survey found only that firms were "considering" relocation, rather than "planning" on it.

He warned that "over pessimistic evaluation of the challenges facing this sector could damage investor confidence and also be misused by competitor countries to negatively impact on Ireland's location for US investment."

US firms directly employ more than 100,916 workers in Ireland, the highest total since 2000 and up from a low of just under 96,000 in 2003.

Some 8.7% of firms are considering winding up their Irish operations entirely.

Around 48% of US firms were considering transferring some business functions out of Ireland and replacing them with other activities here.

However, the survey found that Ireland is one of the most profitable places for US firms to do business. They realised a profit margin greater than 20% on Irish operations in 2005, compared with an 11% margin on all US overseas direct investment. Only USowned operations in China have a comparable margin.

Chamber president and Intel Ireland general manager Jim O'Hara also warned that energy costs in Ireland must be controlled.

"Whoever is involved in forming the next Government needs to be aware that some of the fundamental uncertainties relating to energy costs and supply must be addressed as a matter of priority, " he said. "There must be a plan of concrete action to return energy costs to at most the EU average within three years and maintain that relative position."