The US Senate will debate legislation on immigration reform this week.

It follows a weekend of demonstrations by thousands of illegal immigrants across the US.

There are estimated to be upwards of 12 million undocumented people in the United States, including up to 50,000 Irish people.

The Senate Judiciary Committee is expected to produce legislation on immigration reform that will be debated later in the week on the Senate floor.

It is expected to mirror proposals by the US President, George W Bush, for a guest worker programme.

This proposal has been criticised by opponents because it does not allow a path to citizenship and could create a new underclass.

The McCain Kennedy Bill favoured by the Irish Government would allow people to stay in the US and work while applying for a green card. It also involves paying a fine.

The leader of the Republicans in the Senate, Bill Frist, said he intends to introduce separate legislation that will tighten border controls.

Even if the Senate is successful in passing legislation, it must reach a compromise with a bill passed by the House of Representatives in December that makes illegal immigration a crime.

The debate is expected to last for at least two weeks.