The disaster, with a combined death toll in Turkey and neighbouring Syria exceeding 41,000, has ravaged cities in both countries, leaving many survivors homeless in near-freezing winter temperatures.

Turkish President Tayyip Erdogan has acknowledged problems in the initial response to the 7.8 magnitude quake that struck early on February 6 but has said the situation is now under control.

“We are facing one of the greatest natural disasters not only in our country but also in the history of humanity,” Erdogan said in a televised speech in Ankara.

Those rescued on Tuesday included two brothers, aged 17 and 21, pulled from an apartment block in Kahramanmaras province, and a Syrian man and young woman in a leopard-print headscarf in Antakya rescued after over 200 hours in the rubble. There could be further people alive still to find, said one rescuer.

But UN authorities have said the rescue phase is coming to a close, with the focus turning to shelter, food and schooling.

“People are suffering a lot. We applied to receive a tent, aid, or something, but up to now we didn’t receive anything,” said Hassan Saimoua, a refugee staying with his family in a playground in Turkey’s southeastern city of Gaziantep.

Saimoua and other Syrians who had found refuge in Gaziantep from the war at home but were made homeless by the quake used plastic sheets, blankets and cardboard to erect makeshift tents in the playground.

“The needs are huge, increasing by the hour,” said Hans Henri P Kluge, the World Health Organization’s director for Europe. “Some 26 million people across both countries need humanitarian assistance.”

“There are also growing concerns over emerging health issues linked to the cold weather, hygiene and sanitation, and the spread of infectious diseases – with vulnerable people especially at risk.”

At a Turkish field hospital in the southern city of Iskenderun, Indian Army Major Beena Tiwari said patients had initially arrived with physical injuries but that was changing.

“Now more of the patients are coming with post-traumatic stress disorder, following all the shock that they’ve gone through during the earthquake,” she said.

Families in both Turkey and Syria said they and their children were dealing with the psychological aftermath of the quake.

“Whenever he forgets, he hears a loud sound and then remembers again,” Hassan Moaz said of his nine-year-old in Aleppo, Syria. “When he’s sleeping at night and hears a sound, he wakes up and tells me: ‘Dad, aftershock!’”

A first convoy of UN aid entered rebel-held northwest Syria from Turkey via the newly-opened Bab al-Salam crossing.

Syrian President Bashar al-Assad agreed on Monday to allow UN aid to enter from Turkey via two more border crossings, marking a shift for Damascus which has long opposed cross-border aid deliveries to the rebel enclave.

Nearly nine million people in Syria were affected by the earthquake, the United Nations said, as it launched a $US400 million ($A574 million) funding appeal.

The search for survivors was about to end in the north west of Syria, said the head of the White Helmets main rescue group, Raed al Saleh.

Russia also said it was wrapping up its search and rescue work in Turkey and Syria and preparing to withdraw.

The Turkish toll was 35,418 killed, Erdogan said. More than 5814 have died in Syria, according to a Reuters tally of reports from Syrian state media and a UN agency.

Survivors joined a mass exodus from earthquake-hit zones, leaving their homes and unsure if they can ever come back.

More than 2.2 million people have left the worst-hit areas already, Erdogan said, and hundreds of thousands of buildings have become uninhabitable.

-AAP