A French union has accused its national railway of keeping black and Arab employees out of sight when Israeli President Shimon Peres visited Paris to avoid him coming into contact with Muslims, and an investigation has been launched.

The SNCF state railway concern and the Israeli Embassy denied the accusations.

The Sud Rail union said the workers, employed by Itiremia, a subsidiary of SNCF, were deliberately kept off a rota when the station master selected extra staff for Peres's arrival by train at the Gare du Nord station last month.

Other black and Arab workers were asked to stay away from the platform where Peres, who was on a European tour, would be disembarking, and workers were told the reason was "for their own security", the union said in a statement.

"The manager of the site went 'shopping' among his staff to exclude blacks and Arabs because no Muslims were wanted to welcome the Israeli head of state," the statement said.

The Itiremia works council has begun an internal investigation to check the allegations, determine whether discriminatory instructions were issued and who, if anyone, was behind them.

In a statement, the SNCF denied receiving any order from Peres' staff, the Israeli Embassy or the French interior ministry to discriminate among its workers.

It also denied issuing any discriminatory instructions to the Itiremia baggage handling company.

Israeli Embassy spokesman Yaron Ganburg denied allegations that a request for non-Muslim baggage handlers had come from any Israeli body, pointing out that Peres met with Muslim leaders during his trip. "This is a lie, pure and simple," Ganburg said.

Yacine Chaoui, a Sud Rail member in charge of the investigation, said questioning did not reveal evidence of written instructions but that an Itiremia station chief had received oral instructions to keep minority workers out.

"We are convinced there were instructions to discriminate, but we are still trying to determine where they came from," said Chaoui.

Israel is at odds with most Arab and Islamic countries partly because of its unresolved conflict with Palestinians who seek a state on land captured by the Jewish state in a 1967 war.

France's secular tradition forbids keeping official records of people's religious or ethnic background. But advocacy groups argue that discrimination based on "foreign-sounding" names goes largely unchecked.