During times of high unemployment in Ireland, people have tended to flock to the US, often working illegally at first.

However, immigration authorities have toughened up since the 1980s. September 11th led to a crackdown on the number of visas being issued, according to Ms Paula O'Sullivan of Emigrant Advice.

Unless a member of your immediate family is a US citizen, Irish people usually need an offer of employment from a US employer, who will apply for a temporary worker's H1 visa on your behalf. The number of these being issued is now "way down", Ms O'Sullivan says.

Thousands of Irish people used to be able to obtain a H1 visa in order to work for firms like Microsoft, but this is not so common since the end of the tech boom, she explains. "A lot of companies don't want to have to deal with the bureaucracy of proving that you are not taking a job away from a US citizen," she says.

An Irish company with offices in the US may apply for an L1 visa on behalf of a member of staff, allowing them to live and work in the US for up to three years. These visas expire when the work assignment ends.

Students can also live and work in the US for a short period under the J1 visa scheme. However, tighter regulations in US immigration policy triggered a delay in the issuing of some of these visas this year.

Getting a green card to the US is extremely difficult, unless a member of your immediate family is a US citizen. In October of most years, US immigration authorities hold a green card lottery to which people born in Ireland may apply. But the lottery has produced few Irish winners in recent years.

"Only 330 people from the Republic were selected last year and a very small number from Northern Ireland. The previous year only 70 people were selected," says Ms O'Sullivan.

People who overstayed their US visa by six months cannot then apply for the green card lottery, while people born in the UK cannot apply.

Canada is also "extremely difficult" to get into, according to Ms O'Sullivan. "You have to be extremely skilled and have a job offer," she says. "You would have to be working for two years before you go in the skill that you were qualified to do. So someone who qualified as a teacher who is now working at something else won't be able to count that qualification."

Further information is available from Emigrant Advice at www.emigrantadvice.ie and 01 873 2844.