The unions said they would meet at the end of this month to assess the government's response to Thursday's walk-out, which virtually shut down public transport across the country, and could hold another strike in mid-November.

Trade union resistance to the proposed pension reform is seen as the first test of Sarkozy's ability to push through the changes that were a central part of his campaign pledges.

"The eight rail workers' trade unions have decided to meet again on October 31 in order to assess the answers provided by the government," Didier Le Reste, head of the CGT union's rail branch, told reporters after a meeting of rail unions.

"If the plan ... is not revised, the federations have committed themselves to holding a strike in mid-November that could be extended," he added after the talks in a Paris suburb.

The decision was a show of unity after a split emerged between most rail unions, which have since ended their strike, and two hardline groups that continued their walk-out on Monday.

Metros, buses and trams were back to normal but regional train services were still heavily disrupted in some places.

The Sud Rail and Force Ouvriere unions were set to meet later on Monday to decide whether to carry on striking over the plan to end the right of a minority of state workers to retire after 37.5 years, compared with 40 years for most other workers.

DEEP DIVISIONS

The two unions' continued action badly disrupted services on Paris's regional RER service, and state rail operator SNCF said there would still be a reduced service on some RER and train lines in the Paris region on Tuesday.

But six other unions have already gone back to work in a sign of deep divisions over a reform that enjoys broad public support.

"We are making life worse for the tens of thousands of people who are going to work, whereas if we were united we would be stronger," Francois Chereque, head of the moderate CFDT union, told LCI Television.

"The action of the FO (Force Ouvriere) and the Sud Rail doesn't achieve anything."

Sarkozy has said the government is open to discussions on some points of his plan to reform some pensions but has promised to stand firm on the key issue of increasing the contributions period needed to ensure a full pension.

Labour Minister Xavier Bertrand met the management of the SNCF, the RATP Paris transport company and EDF and Gaz de France, the power and electricity companies on Monday afternoon.

"Everyone must be persuaded that there is more to be earned from negotiating than from conflict," he said.

Unions have also called for demonstrations on November 20 to protest against government plans to cut the number of civil servants, and to call for measures to boost purchasing power.