Lebanon wants talks to demarcate its maritime border with Syria, so that it can begin offshore gas extraction after reaching a similar agreement with Israel, its top negotiator told AFP.

Last month - despite the countries technically remaining in a state of war - Israel and Lebanon struck a US-brokered sea border agreement that will potentially open up lucrative offshore gas fields.

Beirut now wishes to define its maritime borders with Syria, to the north, and Cyprus, to the west, to consolidate its offshore rights.

"The Lebanese government must engage directly and publicly with the Syrian government... and publicly demarcate our sea borders," Elias Bou Saab told AFP in an interview Tuesday.

"Any future government must undertake this task and put Lebanon's interest first," he insisted, while "leaving regional political conflicts out of this matter."

Syria, which once had a controlling hand in Lebanon's affairs, has repeatedly refused to delimit land and sea borders with its neighbour.

According to Bou Saab, the disputed maritime area between Lebanon and Syria is "perhaps more than 800 square kilometres (310 square miles)".

It could be "larger than the disputed area with Israel", he added.

Lebanon cannot begin gas exploration in the northern part of the waters off its Mediterranean coast without first resolving its border dispute with Syria, Bou Saab said.

And Lebanon also needs an agreement with Syria to be able to trace its Exclusive Economic Zone (EEZ) with Cyprus.

The Lebanese presidency announced in late October that a delegation would travel to Damascus to discuss the issue, but the trip did not take place.

Syria's ambassador to Beirut, Ali Abdel Karim Ali, spoke of "confusion" around the date.

But Bou Saab, the deputy speaker of parliament and close to outgoing President Michel Aoun, said Syria had "demands and reservations".

Lebanese security officials and politicians have made several visits to Syria in recent years, but almost exclusively in their personal capacity or on behalf of political parties that support President Bashar al-Assad, including the powerful Hezbollah movement, supported by Iran.

The Shia movement's military wing has been fighting alongside Assad's forces since the early stages of the conflict.

Lebanese officials are betting on the potential revenues from the country's offshore energy reserves to try to revive its devastated economy, which has been mired in crisis since 2019.

But Lebanon has been without a president since the beginning of the month, with lawmakers unable to agree on a successor.