Syria's opposition warned on Tuesday of a "humanitarian disaster" in the Damascus suburb of Moadamiyet al-Sham, accusing the regime of a campaign to "starve and displace" its residents.

"Moadamiyet al-Sham is experiencing a humanitarian disaster," said the National Coalition.

President Bashar al-Assad's "regime is carrying out a systematic campaign to starve and displace Moadamiyet al-Sham and intensifying its destruction and demolition of residential buildings in the area," it said in a statement.

It warned the fighting between regime troops and rebel forces had caused the deaths of dozens of civilians and forced many to flee.

The Coalition said the suburb southwest of the city had been under a regime siege for months creating food shortages that saw at least four children and three women starve to death.

Water supplies had been interrupted by bombardments, and schools closed down.

"The Coalition calls on the international community to assume its responsibilities towards the besieged areas of Syria by opening safe humanitarian corridors," the statement said.

"The Coalition calls on international relief agencies to enter Moadamiyet al-Sham and deliver essential humanitarian aid to its residents and to evacuate hundreds of people who face death by starvation."

Moadamiyet al-Sham is one of several Damascus suburbs where rebels seeking to overthrow the Assad regime have set up rear bases from which to attack the capital.

They regularly fire mortar rounds from the city's outskirts into its centre, and regime forces have been trying for months to oust them from the area.

It was also one of the sites reportedly targeted in an August 21 sarin gas attack that killed hundreds of people and sparked international concern.

The United States accused the regime of the attack, a charge it denied, and threatened military action in response.

Instead, Damascus agreed to a US-Russian deal under which it will turn over its chemical weapons arsenal for destruction.