The May Day actions are the latest in a series of large protests by Hispanic groups against proposals to make illegal entry into the US a crime.

"We've unequivocally called on all families to participate in the Great American Boycott and the marches.

"That translates into not going to work, not going to school, not shopping and not selling," said Nativo Lopez, of the Mexican-American Political Association, one of the main organisers.

Street protests are set to continue, and police in Los Angeles expect up to half a million people to take part in a rally.

In New York, thousands of workers will link arms with shoppers to show their support for the campaign.

In Mexico, immigrant rights groups have called for a day-long boycott of US products in support of the protests.

Criticism

The strike is expected to affect companies that rely on low-wage labour, and food producers including Tyson and Cargill have said some of their plants will be closed on Monday.

"We share many of the same concerns about some of the  proposals in Washington," said Cargill spokesman Mark Klein.

However, George Bush, the US president, has criticised the strike, saying, "I'm not a supporter of boycotts. I'm a supporter of comprehensive immigration."

Congress passed a bill in December making illegal entry into the country a crime, and the bill is being debated by the Senate.

There are an estimated 11.5 million illegal immigrants in the US.