Four Lebanese ministers have quit over a constitutional change that allows the president to run for re-election.
Jumblatt is an ally of Syria but opponent of Lahoud
Three ministers from a Druze faction and Environment Minister Fares Boueiz, a Christian, all voted against the amendment in parliament last Friday.
Critics of the move say it was imposed by Syria, which wants President Emile Lahoud to stay on for three more years.
Until last week, the constitution barred presidents from serving more than one term in succession.
BBC Beirut correspondent Kim Ghattas says that Syria's less than subtle interference in Lebanon's presidential elections has drawn widespread criticism from inside and outside the country.
Last week the UN Security Council passed a resolution criticising Syria's continued domination of its smaller neighbour.
The three from Druze leader Walid Jumblatt's secular leftist bloc - one of whom is actually a Christian - said they would submit their resignations to Prime Minister Rafik Hariri on Tuesday.
Mr Jumblatt is a traditional ally of Syria, but analysts say he is known not to be afraid of standing up to Damascus when he thinks it oversteps the mark.
"It is not natural that I should remain in a government with which I differ on a pivotal national issue," Mr Boueiz told reporters after submitting his resignation.
The former foreign minister comes from the Maronite heartland of Kesrouan - a stronghold of opposition to Syria's continued presence in Lebanon.
It has been a bruising political battle over Syria's role
The Jumblatt faction trio are Marwan Hamadah (economy and trade minister), Ghazi Aridi (culture minister) and the Christian politician Abdallah Farahat (displaced persons minister).
The issue of whether Emile Lahoud can stand for a second term in office has turned into a bruising political battle over Syria's role.
Damascus has kept thousands of troops in Lebanon since the civil war.
But many Lebanese view this as an unwarranted intrusion in their internal affairs.
On Friday, 96 deputies voted in favour of changing the constitution to allow Mr Lahoud to stay on - in accordance with Syria's wishes.
Twenty-nine deputies voted against giving him the three-year extension.
Lebanon has a factionally-based system, with members of the various religious groups holding the same portfolios in successive administrations.