The head of the United Nation's World Food Program (WFP) warned of the humanitarian situation in southern Turkey and referred to the "apocalyptic" scenes as he confronted during visit to the quake-hit regions in the country.

More than 50,000 people have lost their lives in the deadly earthquake that killed parts of Turkey and Syria on February 6.

WFP Executive Director David Beasley said, "There is only one way to describe what I saw today: apocalyptic," following his visit the city of Antakya in Turkey's Hatay province.

"Entire neighborhoods have been flattened; homes destroyed, schools and shops closed; lives torn apart. The scale of devastation here is truly incomprehensible," he said.

The official added in a statement that the situation on the Syrian side amounted to a "catastrophe on top of a catastrophe", referring to the past 12 years of civil war. 

The WFP said Beasley visited a UN logistics hub where trucks are loaded with food and other emergency supplies before crossing over into northwest Syria.

He stressed the urgency of scaling up food deliveries to Syria "through all routes - without any restrictions", and called for "all parties to facilitate access". 

Northwest Syria, controlled by anti-Syria militants, and which has a population that was already dependent on aid for basic needs, was the area of the country worst hit.

Increasing aid deliveries are linked to the opening of additional crossings from Turkey into rebel-held areas.