Brazil hoped the law would be revised "to avoid violating the rights of millions of foreigners who peacefully live and work in the United States," it said.

Arizona's law is due to take effect in three months, after being tweaked to allay some contentious language giving rise to fears of racial profiling and overreaching police powers.

The measure requires police to detain, based on "reasonable doubt," any person they suspect of being an illegal immigrants in Arizona, a state believed to be hosting 460,000 undocumented inhabitants.

It remains a deeply polarising piece of legislation, both within the United States - where it has prompted head-shaking by the federal government - and in Latin America, where most immigrants to the United States come from.

Mexico has already called the law "racial discrimination" and warned its citizens about travelling to Arizona.

Brazil, Latin America's biggest economy and a temporary member of the UN Security Council, has more than a million nationals living in the United States, according to estimates.

Brazilian President Luiz Inacio Lula da Silva was on Tuesday attending a summit of the Union of South American Nations (UNASUR) in Argentina that was to address the controversial Arizona law.

The 12-nation summit was expected to issue a declaration blasting the Arizona legislation.