Hundreds of people on Thursday attempted to march on parliament to protest against moves by lawmakers to extend the term of the 128 seat legislature for up to an additional 18 months.

Violence broke out after protesters found their intended route to parliament blocked by police.

"The Lebanese people went to the streets to defend democracy," said protester Hani Morad.

"It's not allowed for any member of parliament to behave like a dictator."

Parliament has already postponed elections scheduled for June over concerns the conflict in Syria may inflame tensions in the fractious country.