Ko Ni, a Burmese Muslim and a long-standing adviser to the country's leader Aung San Suu Kyi, was shot in the head by a lone gunman outside Yangon International Airport after returning from a government-led trip to Indonesia.

Police arrested a suspected 53-year-old gunman as he attempted to run away.

Witnesses said a taxi driver who chased the gunman was also shot.

His condition was not immediately known.

Police said the gunman, who was being interrogated late Sunday night, was from Mandalay but gave no further details.

While the motive for the assassination was not immediately known Mr Ko Ni's death will rattle the nerves of minority Muslims as Myanmar's army wages a brutal crackdown on Rohingya Muslims in western Rakhine state.

With Mr Ko Ni in the delegation to Indonesia were several Myanmar Muslim leaders, including Rohingya.

Myanmar's government has denied reports of widespread human rights abuses in Rakhine, saying the security forces are responding to attacks by Muslim extremists.

Mr Ko Ni was a practising lawyer who had handled more than 900 criminal cases and 1,400 civil cases.

He was a patron of the recently formed Myanmar Muslim Lawyer's Association.

Fairfax Media