Police and the military have in recent weeks rounded up people for allegedly spreading communism - which remains outlawed in Indonesia - through logos on T-shirts.
They have also seized books about communism and stopped a film screening that touched on the subject.
It came after the government last month took timid steps towards making peace with one of the nation's darkest chapters - the killing of at least 500,000 people in anti-communist massacres in 1965-66, conducted by local groups with military support.
During his rule, the massacres were presented as necessary to rid the country of communism - Indonesia had the world's third-biggest communist party before the killings.
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Public debate about the killings was taboo, and no one was ever held to account.
Since Suharto's 1998 downfall and Indonesia's transformation into a freewheeling democracy, there have been growing calls to re-examine one of the worst mass killings of the 20th century, and even for an official apology.
But the moves swiftly sparked a backlash from the military and police.
Conservative elements of the security forces began speaking out against a supposed communist resurgence, despite the fact the Indonesian Communist Party (PKI) was wiped out during the 1960s massacres.
"The leftist movement is currently surging in this country," hardline Defence Minister Ryamizard Ryacudu warned in a recent speech to hundreds of retired generals, according to the Jakarta Post newspaper.
Paul Rowland, an independent Jakarta-based political analyst, said some in the military "would like to revive the communist threat because that effectively justifies the actions that were taken 50 years ago".