* Workers want talks with management over pay-union
* Strike could pinch consumers if prolonged
* LNG accounts for third of France's gas supplies (Updates with details, background)
PARIS, April 17 (Reuters) - Workers at GDF Suez liquefied natural gas (LNG) terminals in southern and western France were blocking the unloading of vessels to demand a better sharing out of profits, and prolonged action could lead to shortages, the CDT union said on Tuesday.
Two vessels were blocked at Fos Tonkin and Fos Cavaou near Marseilles on the Mediterranean, the union said. The workers will not unload another vessel expected at the Monitor LNG terminal on the Atlantic, although the union did not say when the ship was due. All operations were expected to stop at the terminal.
The strike could lead to gas shortages if the action is prolonged because of a combination of low gas storage levels and cold weather, which is forecast to continue through next week, pushing heating demand higher, the union official said.
The strike kicked off just days before France's presidential election. The state has reduced its ownership in GDF over the past few years to 36 percent, and the workers want to make a point that the government should take a more active role in protecting their rights and the interests of the public, a union official said.
LNG accounts for around third of gas supplies in France.
The workers are calling for a meeting with management to discuss a raise in their annual bonus to reflect the higher profits of the company, a CDT union official said, adding that no meeting had yet been scheduled.
GDF Suez confirmed the strike but declined to comment further.
The blocked vessels at Fos Cavaou and Fos Tonkin were the Cheikh Bouamama, with an LNG capacity of 74,000 cubic meters, and Al Gharrafa, of 216,000 cubic meters, according to AIS Live ship-tracking data on Reuters.
French LNG workers last downed tools for two weeks in autumn 2010 as part of wider strike to combat pension reforms.
French utility GDF Suez took full control of Britain's International Power on Monday through a sweetened offer of 6.4 billion pounds ($10.2 billion), leaving the world's biggest independent power producer better placed to win contracts in fast-growing emerging markets. (Reporting By Muriel Boselli; Additional reporting by Marion Douet and Karolin Schaps; Editing by Jane Baird)