France's upper House, Senate, has voted to approve a landmark bill granting homosexual couples the right to marry and adopt, after a heated debate and mass protests from conservatives and religious groups.

The vote on Friday, by a show of hands, puts the bill on track to become law within weeks after a second reading in the lower House, National Assembly.

The ruling Socialists said the bill would return to the National Assembly by Wednesday - far earlier than the expected date of May 20.

Opponents accused them of seeking to rush through the law, with the head of the right-wing UMP's faction in the assembly, Christian Jacob, saying President Francois Hollande was "risking a violent confrontation with the French people" over the bill.

Senators had earlier approved crucial articles of the bill granting gay couples the right to marry and to adopt.

Christiane Taubira, the justice minister, hailed the Senate vote, saying it had strengthened French society "by granting the simple recognition of full citizenship to homosexual couples".

The bill came under vehement attack in a country that is officially secular but predominantly Catholic, mobilising hundreds of thousands of people in pro- and anti-gay marriage protests nationwide.

In January, hundreds of thousands of demonstrators flooded into the capital, Paris, for an anti-gay marriage march.

Last month, police were forced to fire tear gas on people protesting against the bill, and dozens were arrested.

Call for referendum

Opponents had said they would organise another mass protest in Paris on May 26 if the law was approved, to demand its withdrawal and a referendum.

The bill was largely supported by the ruling Socialists, their allies in the Green Party and the Communists, and opposed by the main opposition UMP and other right-wing and centre-right parties.

"We are overwhelmed with pride by this vote to move our society forward," said the head of the Socialists in the Senate, Francois Rebsamen.

But opponents slammed the adoption of the bill, with right-wing former Prime Minister Jean-Pierre Raffarin saying it would cause a "rupture" in society.

Opposition to the bill has been forceful and gay activists and rights groups say reports of verbal and physical assaults against homosexuals have surged amid the debate.

Rights group SOS Homophobie said this week it had registered a 30 percent rise in reports of assaults on homosexuals last year compared to 2011, with a marked surge when debate began in the autumn.

Opinion polls have routinely indicated that a majority of French people support gay marriage but that fewer support adoption rights for homosexual couples.

Hollande championed same-sex marriage and adoption during his election campaign last year.

Source: Agencies