Indonesian military and police have seized the West Papua National Committee headquarters in the Southern city of Timika.
Dozens of officers descended on the building on Monday, tearing down walls and ordering an end to operations.
The Jakarta Post reported the local district police chief saying 80 military and police personnel monitored New Year celebrations at the headquarters on Monday.
Agung Marlianto said officers ordered Free West Papua activists to remove all insignia and not to shout freedom slogans.
Officers painted over and knocked down walls displaying the red and white colours of the independence movement.
Mr Marlianto said Papuans won't be allowed to use any Free West Papua symbols, including the Morning Star.
West Papua National Committee spokesperson Ones Suhuniap told the Jakarta Post the takeover was immoral and improper.
The committee's headquarters will now be used as a joint military-police post.