While these kinds of scams have been reported for years, authorities said they appeared to be increasing.
"Virtual kidnappings ... have developed considerably over the last decade by transnational organized crime syndicates," said NSW Detective Chief Superintendent Darren Bennett in a statement.
Last year, there were 1,172 reports of what police call "Chinese authority" phone scam across Australia. It's unclear how many of these were attempts to coerce fake kidnappings or the other scenario of depositing money into offshore accounts, and if all were successful.
Authorities said scammers targeted Chinese international students, in particular, but they also tried Australian and international victims from non-English speaking backgrounds.
The 2019 scams saw a loss of more than 2 million Australian dollars ($1.43 million), according to NSW police.
In 2018, the federal police said there were nearly 1,700 scam calls reported, resulting in losses of nearly 1.2 million Australian dollars ($855,000).
Similar scams have been reported across the United States, targeting Chinese students and other minorities.
The Chinese Consulate General of Chicago warned in 2018 that some of the more sophisticated scammers have even hacked into the mission's phone lines, calling or leaving voice messages to victims in the consular district.
That year in Canada, three students went missing in the Toronto area, prompting a citywide search. They were later found by police, who said it was likely a faked kidnapping ordered by scammers.
Unfortunately, these types of crimes are very difficult to investigate due to the use of encrypted messaging apps, techniques to alter host phone numbers, hacking and offshore accounts, Australian detective Bennett said in a news conference on Monday.
"Our message today is one of prevention," he said. "The overwhelming message is to don't pay any money ... Call the authorities, or just hang up."