Open Society, founded by American billionaire George Soros, has helped fund Myanmar media outlets and civil society groups for years.

State media announced on Monday that authorities had accused the organisation's local branch of directing funds to the civil disobedience campaign opposing military rule in the country.

Bank accounts belonging to the organisation's local branch had been frozen and last week an Open Society finance officer was taken into custody last week, according to the Global New Light of Myanmar newspaper.

Arrest warrants had been issued for another 11 Open Society employees, the report added.

The New York-headquartered Open Society said Tuesday there was no truth to the claim it had illegally used funds and called for the "immediate release" of the detained finance officer.

"We are alarmed by reports that authorities are seeking to interrogate other staff members," a statement from the group added.

"These allegations suggest a worrying attempt to attack and discredit those who wish for a return to peace and democracy in Myanmar."

A nationwide uprising has seen massive crowds take to the streets of cities around Myanmar demanding the military relinquish power and release ousted civilian leader Aung San Suu Kyi, who was deposed in a coup six weeks ago.

The junta has increasingly deployed heavier force to quell the demonstrations, with more than 200 protesters reported killed in the crackdown.