This is the pair's first joint trip to the US

During the week-long visit, the first and deputy first ministers will visit the New York stock exchange.

They will also meet the city's mayor, Michael Bloomberg, and other business and political leaders.

The visit culminates with a reception at the White House on Friday where they will meet George Bush.

It is taking place ahead of an economic conference to be held in Belfast in May.

Capital

While in Washington, the ministers will also go to Capitol Hill for discussions with leading members of the Senate and Congress as well as meetings with US Commerce Secretary Carlos Gutierrez and head of the National Security Council Steve Hadley.

Speaking before he left, Mr Paisley said: "Northern Ireland is open for business and is ready to meet the challenges that lie ahead.

The first and deputy first ministers will visit the White House

"We have never been in a better position to boost our economic prospects, but in order to do so inward investment will play a crucial part."

The first minister added that he and Mr McGuinness were going to America "not just to thank them for their help and support in the past, but to impress on them that we are determined to build on the political progress by building a vibrant economy".

Mr McGuinness said: "We would issue an open invitation to businesses to come and see at first hand the attractions we can offer, in terms of the skills our people have to offer and the fact that we are an ideal location."