A top UN official has lauded India's first response and reconstruction assistance to Nepal following a devastating earthquake in April that killed nearly 9,000 people, saying the help has been welcomed by Kathmandu.

"India and China are very very present in the reconstruction effort. We have seen the Indian armed forces providing the first response," UN Development Programme Assistant Administrator and Director of the Bureau for Policy and Programme Support Magdy Martnez-Solimn told reporters during a briefing about his mission to areas of devastation in Nepal and "daunting challenges."

He said the Nepali airport was "literally occupied" by the Indian military aircraft and helicopters that provided support to the Nepalese armed forces after the April 25 temblor. India's help has "been very welcome" by Nepal, he said.