The Taoiseach made the claim as special guest at a gala lunch organised by Londonderry Chamber of Commerce.

The chamber has grown considerably in strength in recent years, both in terms of membership and in the success of its lobbying, and Mr Ahern was the second high profile visitor within five days, the other being First Minister Ian Paisley.

Mr Ahern was introduced to around 350 chamber members at the Everglades Hotel as the prime architect of the Celtic Tiger phenomenon, which he attributed to reducing the reliance on the public sector and slashing the rate of corporation tax.

This, he said, had the immediate effect of attracting 500 US companies wanting to do business in the Republic.

The Irish premier's visit came as the region was reeling from the announcement that Seagate's Limavady plant is to close next year, with the loss of 930 jobs.

Mr Ahern said: "This is a time for redoubling efforts to help those workers who have lost their jobs and also the families of those who have lost their jobs.

"I know the First and Deputy First Ministers, their ministerial colleagues and other representatives started that work immediately.

"We are acutely aware of the impact on the whole region, on both sides of the border, and we are certainly willing to help in whatever way we can."

Mr Ahern said his government's new National Development Plan, combined with the efforts of the Northern Ireland Executive, aimed to improve cross-border infrastructure and that this would have particular benefits for the North West.

He also said the NDP would improve cross-border education institutions, and that quality transport infrastructure was required, which was why his government was also spending money on cross-border roads and City of Derry Airport.

He added: "The North West region stands to benefit hugely from these developments. It is not a question of identifying the problems of the region - we all know what they are.

"It is about implementing solutions. We have set out a joint vision - the North West Gateway Initiative - that involves working together, for our mutual benefit, north and south, to build a better future for the region.

"This involves the local authorities in Donegal, Derry, Strabane and Limavady working together with the key policy-makers in Dublin and Belfast.

"It recognises the key challenges - issues such as infrastructure, air access, communications, education and workforce development, higher education, innovation and science. The two administrations are responding to those challenges.

"Work is well advanced on an integrated, non-statutory spatial planning framework for the North West Gateway. Telecoms connectivity to this region has improved significantly and we are supporting a joint application for major European funding to upgrade the connection between Northern Ireland, via the North West, and north America.

"A cross-border workforce development forum has been established to help produce the skills that employers need."

The Taoiseach said the Celtic Tiger was the product of deliberate policy decisions " sustained by a positive business climate and progressive tax policies".

"Northern Ireland is now in a position to adopt its own strategy. The Executive has been brave. It deserves the support of business," he said.

Mr Ahern challenged business leaders to be forward-thinking, and said there was a need for innovation: "Remember, all the products and all the things that will be success stories in 20 years have not been dreamt of yet."

He added: "The people of this region have overcome enormous challenges. So many people, including the Chamber of Commerce and the people in this room, are working hard to ensure the future is bright.

"If the people of this city and region can achieve what you have already achieved, there should be no limits to your ambitions."