Myanmar's army took over early Monday, taking Suu Kyi into custody and announcing a state of emergency and power transfer to military chief General Min Aung Hlaing.

Dressed in red -- the signature colour of Suu Kyi's National League for Democracy -- the Myanmar protesters in Bangkok hoisted posters of the army chief emblazoned with the words "Shame on you, dictator".

"I woke up today and saw the news that Mother Suu was arrested. I want her to be released," one protester told Thai media.

"The army controlled our country for 50 years and we were suffering."

About two dozen riot police attempted to break up the protest, and clashed with Thai organisers who are part of the kingdom's own democracy movement.

A police spokesman said a handful of people were detained for questioning after Thai protesters threw rocks and coloured smoke bombs.

Thailand's prime minister -- a former army chief who seized power in a coup in 2014 -- has made no public comments about neighbouring Myanmar's putsch, though his number two, Prawit Wongsuwan, said the issue was "a domestic affair".

Ministry of Foreign Affairs spokesman Tanee Sangrat told reporters Thailand hopes for the "current situation to be resolved peacefully and returned to normalcy soon".

There are over a million Myanmar migrant workers in Thailand, according to official figures, but the true number is believed to be much higher.