An Iranian tanker is reportedly discharging a cargo of gasoil in Syria for the benefit of Lebanon's Hezbollah.

Oil intelligence outfit TankerTrackers said on Tuesday that the 35,155-dwt Faxon (built 2004) was delivering 33,000 tonnes of the petroleum product in Baniyas for trucking into Lebanon.

TankerTrackers said the ship was unable to discharge in Lebanon due to sanctions.

It said the National Iranian Tanker Co-managed Faxon is carrying 249,000 barrels of gasoil and that 190 barrels can fit on each truck, necessitating 1,310 truckoads.

Iran has allegedly sent oil cargoes to Syria in the past. The exports to Lebanon, through Iran-backed Hezbollah, were first reported in August.

Lebanon has been suffering a severe fuel shortage, brought on by the country's long-running financial crisis that has seen its currency lose nearly all of its value. Lebanon's government cut fuel subsidies in late August, reportedly causing prices to rise by 66%.

There are as many as four ships with cargoes intended for Hezbollah, a Shiite political party considered by many governments around the world to be a terrorist organisation.

"We could have got a whole fleet of vessels … but we didn’t because we don’t want to aggravate anyone," Hezbollah leader Sayyed Hassan Nasrallah said, according to al-Jazeera.

It is unclear whether or not the Lebanese government approves of the shipments, as new Prime Minister Najib Mikati has not yet commented, the al-Jazeera report said.

The shipments show Iran's resolve to continue extorting oil and petroleum products in the face of strict US sanctions keeping the Islamic republic out of above-board trades.

Earlier this month, oil minister Javad Owji said there was a "strong will" to increase exports.

The Faxon is no stranger to controversial voyages.

The ship was part of a flotilla of Iranian ships that brought gasoline to Venezuela last year.

The shipment saw Iran and Venezuela, two geopolitical foes of the US, renew economic ties.

Iran's relationship with Syria and Hezbollah has been similarly fraught, with Israel allegedly periodically attacking Iranian ships carrying cargo to Syria.