PARIS (AFP) — The French National Assembly early Thursday adopted a government bill tightening the rules for immigrants wanting to join their families in France and giving the nod to DNA tests to prove family ties.

In a late-night vote the bill received support from deputies of the ruling UMP and the New Centre party, while the Socialists, Communists and Greens voted against.

Earlier the lower house of parliament passed a watered-down version of a controversial measure opening the way to DNA testing of would-be immigrants wanting to join their families.

It also adopted the principal measure in the government bill: an evaluation in the candidates' home countries of their knowledge of the French language and the "values of the Republic."

Drawn up by Immigration Minister Brice Hortefeux, the bill imposes new conditions for relatives wishing to join families in France, including knowledge of the French language and proof of financial resources.

But attention focused on an amendment introduced during the committee stage of the bill's passage through parliament, which would authorise genetic tests to provide evidence of kinship.

The measure was adopted Thursday by a vote of 91 to 45. It stipulates that the DNA testing must be entirely voluntary and requested by the would-be immigrant, and would be regarded as experimental, in force till the end of 2010.

The text authorizes candidates for immigration to use DNA tests to prove that they are related to persons already living in France if they come from a country where laws regarding civil status are insufficient.

The amendment's backers in the ruling Union for a Popular Movement (UMP) party said voluntary DNA tests would be useful for families wishing to accelerate the application process, and argued that 11 other countries in the EU already use them.

But the left-wing opposition and many rights groups believe the effect of the bill would be to make DNA tests the general rule, which would exclude many families unable to bear the financial cost.

Thursday's amendment by the government said that contrary to the initial text, immigrants would have their DNA test costs reimbursed if their application was successful.

Another last-minute conciliatory offer by Hortefeux was to set up an independent commission that would look every year into how the tests were being carried out.

An opinion poll Tuesday showed that a large majority of the public wants tougher rules to control immigration.

Seventy-four percent were in favour of immigration quotas, and the same amount supported limiting the right to come to France to those who understand French, according to the OpinionWay survey in Le Figaro newspaper.

Eighty-seven percent were opposed to a blanket regularisation of illegal immigrants, who are estimated to number between 200,000 and 400,000 in France.

The French government aims to deport 25,000 illegal immigrants before the end of the year.