Qatar's emir said on Sunday he was puzzled by the delay in delivering aid to victims of last month's earthquake in Syria, adding that it was wrong to abuse humanitarian aid for political purposes, in an apparent swipe at the Syrian government.

Qatar was among several regional states that backed rebels in Syria's civil war and has previously spoken out against efforts by some countries to normalise ties with Damascus.

Emir Sheikh Tamim bin Hamad al-Thani, speaking at the opening of the U.N. Least Developed Countries conference in Doha, stressed the need to help Syrians "without hesitation" and support Turkey's efforts to recover from the devastating earthquake.

The death toll in Turkey has risen to above 45,000, bringing the total toll including Syria to about 51,000. In Syria, the northwest region controlled by rebels at war with President Bashar al-Assad was the worst hit.

"As I wonder at the delay in the arrival of aid to these(Syrian) people, I stress that exploiting a human tragedy for political purposes is unacceptable," Sheikh Tamim said.

The United Nations has called for access by all parties in Syria, already devastated by years of civil war, in order to scale up aid deliveries.

Relief bodies complain of restrictions by the Damascus government that they say politicise aid distribution. Other aid agencies say hardline rebels have blocked aid deliveries from government-held parts of Syria, further complicating efforts.

Qatar has been providing aid to Syrians via Turkey while other Gulf states like the United Arab Emirates have directly flown in humanitarian supplies.

Doha, like Washington, has voiced opposition to any moves towards rehabilitating or normalising ties with Assad, citing his government's brutality during the conflict and the need to see progress towards a political solution.