LOS ANGELES, March 28: Immigrants, who work illegally in American plants, restaurants and fields, do not have the same rights to restitution as US citizens who are mistreated on the job, a divided Supreme Court ruled on Wednesday.

The court ruled that a plastics company owed nothing to a Mexican man who used a friend’s identification to get a job.

The Bush administration argued that without the threat of punishment for employers, some of the millions of undocumented workers in the United States might be exploited.

Justices split 5-4 along ideological lines on whether companies can be forced to give back pay to illegal workers wrongly fired or demoted.

“Awarding back pay to illegal aliens runs counter to policies underlying” federal immigration laws, Chief Justice William H. Rehnquist wrote in the court’s opinion.

The National Labor Relations Board has been allowing wronged undocumented workers to collect back pay since 1995. The board makes sure that employees are not punished for engaging in union activities and protesting employment conditions. The chief tool is requiring back pay, or restitution.

“This decision has ominous implications for the enforcement of labour laws across the board,” said William B. Gould IV, the board’s chairman from 1994-98. “It will bring into our borders more exploitable low-wage workers.”

As many as seven million undocumented workers have jobs in the United States, the court was told. Six states with high immigration populations had argued that punishments are needed to protect workers.

The Supreme Court has held that undocumented workers are protected by federal labour laws. Justices said in this case that did not entitle them to back pay “for wages that could not lawfully have been earned and for a job obtained in the first instance by a criminal fraud.”

Jose Castro had a minimum wage job operating a plant blender at Hoffman Plastic Compound’s plant in Paramount, Calif. He and three other employees were laid off in 1989 after they supported efforts to unionize the plant. He did not speak English, nor did half of the other plant workers, according to court records. The labour board said Hoffman owed Castro about $67,000.

Hoffman can be subject to “significant other sanctions,” including a requirement that it prominently post a notice to employees about their rights, Rehnquist said in the decision.

“That’s meaningless. That’s simply a slap on the wrist,” said Gould, who now teaches labour law at Stanford University.

Maurice Baskin, Hoffman’s lawyer, said the court used common sense in determining “employers should not be required to make windfall payments to illegal aliens.”

Dissenting Justice Stephen Breyer said the back pay penalty “reasonably helps to deter unlawful activity that both labour laws and immigration laws seek to prevent.”

Joining Breyer were Justices John Paul Stevens, David Souter and Ruth Bader Ginsburg.

CRITICISM: The decision was criticized by immigrant and women rights groups.