A Lebanese military court has sentenced two men to death on charges of spying for Israel's Mossad, a judicial source said.

"Military court chief General Nizar Khalil sentenced Oussama Mohammed Ali Berri, from the southern town of Tebnin, to death for contacting Israeli intelligence and providing information that facilitated Israeli attacks on Lebanon," the source told AFP.

Khalil also sentenced Antoine Salim Atmeh to death "for entering Israel, working with Israeli intelligence and convincing Berri to collaborate with Israel," the source said.

Berri is in custody, but Atmeh remains at large and was sentenced in absentia.

More than 100 people have been arrested on suspicion of spying for Israel since April 2009, including members of the security forces and telecom employees.

Fayez Karam, a former army general and high-profile member of a Christian party allied with Hezbollah, was also charged with spying for Israel this month and providing the Jewish state with information on its arch-foe Hezbollah.

Today's sentence brings to five the number of men sentenced to death since 2009, including one found guilty of aiding Israel during its devastating 2006 war with Hezbollah.

Lebanon and Israel remain technically in a state of war, and convicted spies face life in prison with hard labour or the death penalty if found guilty of contributing to Lebanese loss of life.