Authorities are warning Australia's Chinese community to be wary of a bizarre scam in which students are tricked into posing as kidnapping victims.

The two scams have already bilked about 900 people out of more than $1.5 million this year alone, the ACCC's Scamwatch service said. Credit:Rob Homer

The callers tell the students they've engaged in criminal activity and threaten them with criminal sanctions unless they take photos of themselves bound and gagged.

The photos are then used to extort money from the victim's family by claiming the students have been kidnapped, the Australian Competition and Consumer Commission said on Monday.

That scam and another one has already bilked about 900 people out of more than $1.5 million this year alone, the ACCC's Scamwatch service said.