Taoiseach Enda Kenny raised the plight of illegal Irish immigrants in the US, saying that there was “frustration” among the so-called “undocumented” that American lawmakers had not overhauled immigration legislation to make them legal.

Speaking at the St Patrick's Day breakfast hosted by US vice president Joe Biden at his home in Washington, Mr Kenny said that people were looking to their elected representatives for a solution to the problem.

“St Patrick himself was an immigrant in various ways when he came to Ireland. It is the frustration of people who look at the elected representatives and say why can’t you do these things?” he told guests at Mr Biden’s residence.

“Was it not a famous quotation: ‘I see things that never were and ask, why not?” he told guests at the function in the vice president’s private residence at the Naval Observatory in north-west Washington.

The Taoiseach said that the estimated 50,000 Irish documented wanted a process of legalisation, to pay their taxes, to raise their families and to travel home to Ireland and back to the US and contribute to “this great country.”

“To do that in terms of the numbers who are in this great country is what’s going to make America, is what’s going to regenerate it from generation to generation,” he said.

Mr Kenny said Irish immigrants had “unfortunately suffered disproportionately in respect of the unintended consequences of the 1965 Immigration Act” that made it harder for Irish immigrants to move to the US legally.

The Taoiseach endorsed Mr Biden’s comments at a function last night in which he urged Northern Ireland’s political leaders to “keep going” to complete the peace process in Northern Ireland.

The US Vice President told the gala dinner of the American Ireland Fund in Washington that all sides had a responsibility to complete the work of the Good Friday Agreement.

The Taoiseach commended Mr Biden on “the clarity and the power and the strength,” telling guests that there was a “requirement from those who are left to finish the job” and to bring peace to Northern Ireland.

Speaking before Mr Kenny, Mr Biden praised the Government for its response to the economic crisis, telling him: “You had the courage to make the tough decisions.”

The Government had the faith to see the decisions through and that the “results were in,” noting the economic turnaround, he said.

About 50 guests including Democratic senator Pat Leahy, Maryland governor Martin O’Malley and congressman Joe Kennedy, grandson of the late US senator Robert F Kennedy, enjoyed Irish soda bread, “herbed eggs cups” and country potatoes along with music from an army violinist.

The Taoiseach is meeting president Barack Obama in the Oval Office today and will later travel with the president and vice president to the US Capitol for the traditional St Patrick’s Day lunch hosted by the Republican speaker of the House of Representatives John Boehner.

The traditional shamrock ceremony will take place at a reception at the White House this evening.