The rivals in the French presidential election race are making their final push to win over more than one-third of voters who are still undecided.

Opinion polls suggest that of the 12 candidates standing in Sunday's first round only four are serious contenders for the 6 May run-off vote.

A poll by CSA shows centre-right frontrunner Nicolas Sarkozy on 27% and the Socialist Segolene Royal on 26%.

But rivals may attract many protest votes as disillusionment is widespread.

The main candidates held their last campaign rallies on Thursday evening. Friday is the final day of campaigning - from midnight there will be a blackout on opinion polls and campaign speeches.

Mr Sarkozy is in the southern Camargue region trying to win round farmers.

Ms Royal is continuing her informal style with a Socialist picnic near the city of Poitiers, while the centrist Francois Bayrou focuses on the crucial working-class vote in the north.

On Thursday evening, Mr Sarkozy appeared before 12,000 cheering supporters in Marseille, trying to shed the tough image he gained as interior minister.

"To unite the French people, to be able to speak on their behalf, to be able to govern, you must be able to love," he said.

He was joined on stage by footballer Basile Boli and a range of former prime ministers and ministers.

Thumping rock music

Spain's Socialist Prime Minister Jose Luis Rodriguez Zapatero appeared with Ms Royal in the south-western city of Toulouse.

To the sound of thumping rock music and the cheers of about 15,000 supporters, Ms Royal promised a "fairer and stronger" France - "a France that does not discriminate against a job-seeker because he does not have the right skin color, the right name, the right address".

She got a deafening cheer when she said France would never go down on its knees for US President George Bush.

Not far away, in the town of Pau, Mr Bayrou, leader of the centrist Union for French Democracy (UDF), said rising tensions in France concerned him.

"I want France to be secure and calmed," he said.

Far-right National Front leader Jean-Marie Le Pen, currently polling about 13%, spoke in the party's Riviera stronghold of Nice.

He said a "great national wave will sweep away the oligarchy".

Mr Le Pen came a surprise second in the 2002 election, beating the Socialist candidate to reach the run-off second round, where he was defeated by Jacques Chirac.

This time, there are more than one million newly registered voters, the biggest increase in 25 years. Many of them are young people or French citizens living abroad, whose voting intentions are hard to gauge.

Another novelty is the use of electronic voting machines in some districts, criticized by the Socialists and some other opposition parties as dangerously unreliable. They will be used by 1.5 million voters.

Ms Royal hopes to become France's first woman president, but left-wing voters are among the most volatile, surveys suggest. She has several rivals on the left who could undermine her support.

Photo caption

Centre-right UMP candidate Nicolas Sarkozy