NAZARETH // We don't employ Arabs - so dozens of companies listed in Israel's Yellow Pages plainly state.

The businesses, which include a bus firm, plumbers, electricians and a removal firm, openly advertise under the banner of "Hebrew labour" - a policy to hire only Jews that Israeli civil rights groups say is a violation of the country's anti-discrimination laws.

The groups believe such advertising is one of a series of initiatives that aim to give preferential treatment to Jewish job-seekers over the country's Arab citizens, a fifth of the population.

They say the trend towards "Jews-only" employment practices reflects Israel's rapid shift to the right.

Initiatives from right-wing groupsinclude awarding "kosher" certificates to firms that restrict hiring to Jews and a campaign by orthodox religious communities to boycott businesses who employ Arabs.

Growing anti-Arab sentiment in the parliament has prompted a raft of so-called loyalty bills from right-wing parties, including on employment policies.

Yehuda Weinstein, Israel's attorney general, warned Prime Minister Benjamin Netanyahu in June that a bill drafted by the Yisrael Beiteinu party, reserving many public-sector jobs for former soldiers, was "unconstitutional".

Arabs are generally exempt from army service and would therefore be ineligible for many jobs.

"We're seeing a disturbing trend to create Arab-free workplaces," said Sawsan Zaher, a lawyer with the Legal Centre for Arab Minority Rights in Israel, or Adalah.

"Firms are increasingly confident it will be good for business if they declare themselves opposed to hiring Arab workers."

The controversy over Yellow Pages has highlighted the revival of 'Hebrew labour' practices that predate Israel's creation in 1948.

The policy of segregated employment was originally devised by early Jewish immigrants in Palestine to strengthen their position as they settled among the large native Palestinian population.

Civil rights groups say the bias persists, as the adverts show.

Ron Gerlitz, a co-director of the Association for the Advancement of Civic Equality in Israel, or Sikkuy, said a coalition of nine Israeli rights groups has launched a campaign to put public pressure on Yellow Pages to withdraw the offending advertising.

"Publication by the Yellow Pages of these adverts gives a seal of approval to the refusal by businesses to employ Arabs," he said.

He added that, in practice, thousands of Israeli firms refuse jobs to Arab workers but most are reluctant to publicise the fact. "The 'Hebrew labour' companies are proud to declare their racism," he said.

Yellow Pages defended its inclusion of the firms, saying the term "Hebrew labour" is not illegal.

But Ms Zaher of Adalah said the companies and Yellow Pages are breaking Israel's Equality in Employment Law of 1988.

"The directory does not allow prostitutes to advertise in its pages because prostitution is illegal in Israel, so what is different in the case of these firms?" she added.

Civil rights groups have also been disturbed by a new bill - the latest in a string of "loyalty laws" presented in the parliament over the past two years - that gives priority to employing discharged soldiers in the civil service.

The courts have previously ruled the common practice by Jewish-owned firms of requiring army service when hiring for non-security positions is illegal as it discriminates against most Arab citizens.

In his letter to the prime minister, Mr Weinstein said the jobs proposal violated a 2000 legal requirement to take affirmative action to increase the number of Arabs in the civil service.

A series of targets set by the government have been reduced and the proportion of Arab workers has barely risen above five per cent over the past decade.

Civil rights groups have long complained that Israel's anti- discrimination employment laws are rarely enforced. The government responded in 2008 by establishing a Commission for Equality in Employment.

But Jafar Farah, director of the Mossawa Centre, an advocacy group for Israel's Arab minority, said the commission, police and government bodies were "unwilling" to enforce laws when discrimination occurred against Arabs.

He said the centre had been trying for several months without success to close down a "Hebrew labour" website set up by Lehava, a far-right organisation.

The site promotes companies that hire only Jewish employees and serve only Jewish customers.

Earlier this year Lehava unveiled a scheme to award a kosher certificate to firms barring Arab workers.

The certificate states that "the owner of this business employs only Jews and not the enemy".

Some Orthodox rabbis have given their blessing to the campaign and helped oversee a related boycott of firms that employ Arabs.

Janet Shalom, a lawyer for the commission, said the "Hebrew labour" companies were breaking the law but the legal position of Yellow Pages in publishing the adverts needs investigating.

She said no action had yet been taken against the companies so far because the commission lacked the resources to investigate.