The UN says some of the relief material for survivors of Nepal's earthquake is being held up by customs officials at the country's only international airport.

Spokesman Jamie McGoldrick says the officials are acting as if it's peacetime, not an emergency.

Meanwhile, authorities in Nepal have ruled out the possibility of finding more survivors buried in the rubble from the devastating earthquake - which has killed more than 6,700 people, and injured 14,000.

However, experts say the damage caused by the earthquake could have been a lot worse.

They claim much of the infrastructure in the country has been improved, following warnings about the threat of natural disasters.

Mike Noyes - Head of Humanitarian Response for ActionAid - says the scale of the operation facing teams - is vast: