International scammers are targeting government agency call centres in an attempt to extract money out of staff.
The Department of Internal Affairs said operators were on guard after numerous calls from cyber criminals wanting information about workers.
Spokesperson Raj Krishnan said staff were getting aggressive calls from overseas scammers, seeking job titles and email addresses.
The callers used malicious emails to try and force a financial transaction or gain unlawful access to private information for online scams, he said.
The department was working to have the calls automatically dropped, but Mr Krishnan said staff should always be on high alert.