French Senate house voted Friday night and passed the core article of the pension reform bill to prolong the minimum retirement age to 62.

The article passed with a narrow majority of 186 against 153. The approval to the pillar clause further cemented the pension reform bill passed by the National Assembly in September.

The left-wing oppositions and labor unions have vowed to organize a strike and demonstration Tuesday to protest the move.

French railway unions said it will take an open-ended strike, which may heavily hit the public transport.

The Elysee social councilor Raymond Soubie told local radio Friday morning the government expects the pension reform bill to completely pass all legal hurdles in late October.

According to the state pensions council, if without improvements, France's annual pension deficit is forecast to reach 32 billion euros (44.6 billion dollars) in 2010, and 80 billion euros in 2030.