A government source told Reuters opposition candidates on Saad Hariri’s list had won all the remaining seats in the Beirut region.
“The count is nearly over and it’s a landslide for Hariri’s list,” said the anonymous source.
Before the vote, Mr Hariri’s anti-Syrian bloc had already won nine of the capital’s 19 seats in the 128-member parliament because they were not contested.
The source told Reuters candidates from his list had taken all 10 undecided seats.
The billionaire businessman Saad Hariri was already celebrating with supporters at his villa in Beirut.
“This victory is for Rafik al-Hariri. Today Beirut showed its loyalty to Rafik al-Hariri,” he told the crowd. “Today is a victory for democracy…freedom and sovereignty.”
Despite the celebratory mood, voters denied Mr Hariri the high turnout he sought, with just 28 percent of those eligible casting their ballot.
Beirut had a 34 per cent turnout in 2000 when his father, then cooperating with Syria, also swept the board.
It’s the first round of voting with other regions following suit over the next three Sundays.
Some voters welcomed the poll, the first free of Syria’s influence.
“I voted because I believe in change,” said 27 year-old Basil Eid. “We want Lebanon free of any subordination. We have to rule ourselves by ourselves.”
The election results are broadly predictable in Beirut and the south, but tighter contests are expected in the north and centre of the country, especially among Christian rivals.
The election follows the withdrawal of Syrian troops, which had dominated Lebanon for 29 years.
Critics of Syria, which tightened its grip on Lebanon after the 1975-90 civil war, claim its intelligence chiefs manipulated previous elections in favour of its political partners.
Many Lebanese are unhappy with the current electoral law, designed to favour Syria’s allies in the 2000 election.
Many political veterans will return to the assembly, but crucially Syria will no longer be the sole arbiter of Lebanese politics.