The trouble came after Assaad Thebian, an organiser of the so-called "You Stink" campaign, called for parliament to be "taken back" from political officials.
Lebanon's current political crisis began in July when the closure of a landfill caused rubbish to pile up on Beirut's roadsides, in parking lots and river beds.
"You Stink" emerged as a movement to demand a solution to trash collection but has broadened its target to the entire political class, accused of being corrupt and inept.
Lebanon's last legislative elections were held in 2009, and parliament has twice extended its own mandate, citing internal political divisions and regional instability as justification.
On Sunday, there was a heavy security presence around the central Beirut square housing the parliament complex to keep demonstrators at bay.
Amid pushing and shoving, several protesters and security personnel fainted and were given first aid.
"We are the people and this place belongs to us. Why are we not allowed access?" asked one demonstrator.
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A member of the security forces said: "The right to peaceful protest is established by law, but it is our prerogative to change the direction of protest marches and where they stop."
Ajwad Ayyache, another one of the organisers, charged "parliament is not legitimate" and that "no one demands accountability" from MPs.
Under public pressure, on September 10 the government approved a plan to tackle the rubbish crisis, but campaigners said it was too vague and did not meet their demands.
"Medicines, bread, water... everything is rotten. There is nothing left for the poor in this country," said one demonstrator in his sixties.
"The politicians are all suffering from Alzheimer's," said another.
Lebanon's political system is deeply divided between two main blocs, which has caused months of political paralysis.
One bloc is led by the Shiite movement Hezbollah, allied with Syria and backed by Iran. The other is headed by Sunni former prime minister Saad Hariri, who is supported by Saudi Arabia and the West.
The country has been without a president for more than a year, as a divided parliament has been unable to fill the post despite meeting more than two dozen times.