US President Barack Obama will outline a host of measures tonight that will protect a total of around five million illegal immigrants from deportation, and offer them the opportunity to leave the US and return again without suffering a re-entry ban.
Over four million people are expected to directly benefit from a new scheme which protects people against deportation for three years and offers then work permits.
In order to qualify, the undocumented immigrants have to have lived illegally in the United States for more than five years and have children who are US citizens or legal residents.
They must also pass a background check.
The US president will unveil the full series of executive actions at 1am Irish time tonight, and will then sign them into law tomorrow.
The actions include a provision that will make it easier for some undocumented immigrants to return to their home countries in times of hardship, by offering a waiver on the three year and ten year re-entry bans currently in place.
The measures form three separate strands.
The first is a new deferred action programme which will offer a guarantee against deportation for three years to illegal immigrants who have been in the United States for more than five years and who have children who are US citizens or legal residents.
Subject to a criminal background check, these people will be allowed to remain in the United States for three years, and will be allowed to work, register for social security, pay taxes, and play a full role in American society.
In theory that three year term can be renewed, unless the programme is reversed by a future President or by a new piece of legislation.
There will also be an extension to the Deferred Action Childhood Arrival programme, meaning all people born after 1981 who arrived here illegally but as unaccompanied children before January 2010 will be allowed to stay subject to a renewable three year term.
These young people are known as 'Dreamers', however the Obama executive actions do not extend to offering their parents protection against deportation, unless they have other children who were born in the United States.
As part of this first group of measures, there will be an extension of the hardship clause in the rule that bans illegal immigrants from re-entering the United States once they leave.
Currently anyone who has lived illegally in the US for less than 12 months is barred from re-entry for three years, and if they have been illegal for more than a year, they're barred for ten years.
This could mean illegal immigrants may travel in and out of the US for family emergencies, such as dying relatives or funerals. There will also be a measure to allow lawful residents to petition for special consideration for their spouses and children.
The second set of measures the president will announce relates to a revised set of priorities for immigration enforcement services.
The new plan will mean that the Immigration and Customs Enforcement service cannot deport people who have committed serious criminal offences,
The ICE authorities will only move against people who have been convicted of criminal offences. The focus will shift towards those who pose a serious risk to public safety, and to those who have recently arrived illegally into the United States.
The third strand is designed to boost the US economy by extending visas to those who come to the US to study science and technology. There will also be a new visa programme for entrepreneurs who can demonstrate that they have investors and will be creating jobs in the US.
There are around 50,000 undocumented Irish people in the country.
Earlier on today the Taoiseach called on President Obama to allow undocumented Irish in the United States travel to and from Ireland, while a new immigration and citizenship system is being established.
Mr Kenny said: "I look forward to the President's announcements very much indeed, he signalled this last March when I met him in the White House".
"We've made the point, and all Irish people have made this point very strongly, that we want to see a situation where there's a pathway to citizenship for immigrants in the United States, including the 50,000 from here in Ireland."
Mr Kenny said that while that pathway is being set up, Irish people who have emigrated to the US should have the right to travel to and from Ireland.
"I do hope and I would like to see the President include the right to travel home and back while people set about the path to citizenship," he added.
