The army was out in full force in the capital Beirut and other big cities amid fears of violence in a country that has been in the grip of a bitter political crisis for more than a year.

The head of the General Confederation of Workers of Lebanon, Ghassan Ghosn, said the strike was aimed at forcing the government to raise the minimum wage and address inflation, but said protestors were urged to avoid violence.

Army chief Michel Sleiman -- who is also the man tipped to be elected president if rival political factions can agree -- warned that "any action that could trigger civil conflict is banned."

Demonstrators blocked roads in several parts of the country, including the eastern Bekaa, where protesters burned tyres and a nine-year-old boy was injured by a stray bullet.

In Beirut, dozens of transport workers prevented taxis from reaching the airport, while in the southern coastal city of Tyre, about 140 bus and taxi drivers marched in the streets chanting "we are hungry, we want to eat."

The CGTL is calling for the minimum monthly wage to be tripled from 300,000 Lebanese pounds (200 dollars, 134 euros) to 900,000 pounds.

Consumer prices rose 3.7 percent in the 10 months to October, led by an eight percent hike in food prices, according to the private Institute of Research and Consulting.

The strike follows similar protests in recent weeks that have prompted fears of all-out civil strife with the country embroiled in its worst political crisis since the end of the 1975-1990 civil war.

Lebanon has been without a president since Emile Lahoud stepped down at the end of his term on November 23, with no elected successor because of a standoff between the Western-backed ruling coalition and the Hezbollah-led opposition.

The coalition accused the opposition of using the unions to organise "political demonstrations" and called on the people of Lebanon "not to be drawn down into a climate of threats and terror and to continue to live life as normal."

Parliament is due to hold a vote on February 11 to elect a president but the previous 12 sessions have been cancelled.