Witnesses said there were clashes on the streets of Corniche al-Mazraa, a mainly Muslim Sunni neighbourhood, as protesters tried to block roads with sand.

Riot police and the Lebanese army fired tear gas to disperse the crowd, while protesters hurled stones at the security forces, burned tyres and set rubbish bins on fire.

"We do not accept a prime minister who was imposed on us," the protesters chanted, many of whom were followers of former premier Saad Hariri.

It was the latest bout of violence that Lebanon has seen since protesters took to the streets on October 17, accusing the country's ruling elite of mismanagement and corruption.

Hariri resigned from the premier's post nearly two weeks later.

On Thursday, Lebanese President Michel Aoun asked Diab, a university professor, to form the new government after binding consultations with parliamentary blocs, breaking a weeks-long political stalemate in the country.

Diab's critics have called instead for a new government of independents.

The designated premier denied he is a Hezbollah candidate.

"I confirm that I am competent and independent, and my orientation is that the government is indeed the government of independent specialists," Diab told reporters after a meeting with Hariri on Friday.

Lebanon's ongoing street protests and its deepening economic crisis, the worst since the 1975-90 civil war - have raised fears worldwide that the country will descend into chaos.

Australian Associated Press