Malaysia's Mahathir, 93, on never missing meetings: It's my duty

President Rodrigo Duterte on Thursday made light of his penchant for daytime dozes after his office said "power naps" had caused the gruff leader to miss a number of key meetings at a Singapore summit.

"What's wrong with my nap?" the 73-year-old told reporters as he arrived at the summit venue on Thursday morning for another long day of meetings.

He is the oldest person ever to be elected president in the Philippines, but he is far from the most veteran world leader attending ASEAN.

That accolade goes to Malaysia's Prime Minister Mahathir Mohamad, who is 20 years older than Duterte and currently the world's oldest leader.

"I don't know how I manage," Mahathir told AFP at the end of the summit when asked how he manages to keep up with the frenetic diplomatic schedule.

"I always attend meetings. It's my duty. If I can, I will. If I'm sick, I won't," he added.

Duterte is attending the annual Association of Southeast Asian Nations (ASEAN) meeting alongside a string of world leaders including Russia's Vladimir Putin, Japan's Shinzo Abe, Chinese Premier Li Keqiang and US Vice-President Mike Pence.

Duterte's no-shows on Wednesday prompted a statement from his office explaining he had only had three hours of sleep the night before.

"He took power naps to catch (up) on sleep," presidential spokesman Salvador S. Panelo said, adding that "some quarters are making a big fuss of the president skipping a few meetings".

"We assure the nation that his aforementioned absence has nothing to do with his physical health and wellbeing which have been the subject of speculation," he added. —report from Agence France-Presse