UN aid chief Martin Griffiths appealed today to remember thousands of people who need shelter and food while rescuers kept searching for survivors of the devastating earthquake that hit southern Turkey and northwestern Syria.

Speaking during a news briefing in the Turkish province of Kahramanmaras, as rescuers worked behind him, Griffiths said he spoke to families who had been displaced and left cold and hungry by the quake.

"I am here to make sure these people are not forgotten," he told reporters.

Griffiths praised Turkey's response to the disaster as "extraordinary" and hailed the "courage of first responders working 24 hours, all the time, hoping for one more sound, one more person who survived."

"It's the beginning and in my experience, people are always disappointed in the beginning," he said, in an apparent reference to criticism over the response to the quake.

He said what happened in the area around the epicentre of the quake was the "worst event in 100 years in this region."

He apparently meant the region's worst natural disaster: Monday's earthquake was Turkey's most devastating since 1939. Syria's 11-year civil war, which has killed hundreds of thousands and made millions homeless, remains the region's deadliest event in recent history.

Griffiths said he was launching a three-month operation for both Turkey and Syria to help pay for the costs of operations there.

Griffiths also told Reuters he hoped in Syria aid would go to both government and opposition-held areas, but that things with this regard were "not clear yet".

Rescuers in opposition-held areas have criticised the United Nations and the international community for not responding quickly enough to the urgent needs there.

- Reuters