US capital could make Ireland more prosperous than ever, and the Republic must maintain its position as the leading location for US investment, the Tanaiste and Minister for Enterprise, Trade and Employment, Ms Harney, said yesterday.

Speaking on the first day of a week-long trade mission in North America, she stressed that as well as touting for new business, she would be encouraging companies that already have an Irish base to expand.

"I firmly believe that we must recognise the enormous potential that there is for jobs growth and expansion in the companies already doing so well in Ireland. Promoting foreign investment is as much about continuing to satisfy our existing customers as it is about looking for new customers," the Tanaiste said.

Speaking on her arrival in Chicago, Ms Harney said US investors were one of the most important drivers of new growth in the Irish economy. "Their interest and commitment to Ireland has been sustained for well over 25 years, and much of the employment growth and prosperity of business in Ireland now and into the future is directly attributable to them."

An intensive schedule for the week will see Ms Harney, who is accompanied by the chief executive of IDA Ireland, Mr Kieran McGowan, meet the top management teams of more than 20 companies. She will also address a number of meetings, including the Irish-Canadian Chamber of Commerce, and the Irish-American community in San Francisco.

The Tanaiste said she also wanted to reinforce and support the positive position which many Irish managers had created for themselves within US companies, and the strong impression their management skills had made on a corporate level.

Nearly 500 US companies in the Republic directly employ 65,000 people, and represent almost half of all foreign companies. They account for over one third of exports from the State and are concentrated mainly in electronics, software, pharmaceuticals, healthcare, financial services, telesales and back offices.