Prominent activist Jack Wanggai was sentenced to three-and-a-half years in prison and 10 others were given three years over peaceful protests in March 2007, lawyer Yan Christian Warinussy told AFP.

The sentences were increased by the High Court in the Papua provincial capital Jayapura on Thursday after prosecutors in Manokwari city, where the protests took place, appealed the decision of a lower court there to jail the activists for eight months each, Warinussy said.

'The activists were carrying out peaceful demonstrations... and they brought the Morning Star flag,' he said.

'The court said that if it didn't deal with this case harshly then it will set a bad precedent for all of Papua.'

He said the defendants planned to appeal to Indonesia's Supreme Court.

Separatist sentiment runs deep in Papua, which lies on the western end of New Guinea island and was incorporated into Indonesia after a 1969 UN-sponsored vote of select tribal elders widely dismissed as a sham.

Displaying banned separatist symbols such as flags in Indonesia can lead to sentences up to life in prison. -- AFP