Cyber insurer Emergence has extended its coverage to include social engineering theft and “crypto-jacking”.

Social engineering theft covers phishing, business email compromise, fake invoices and tricking targets into surrendering login details.

Crypto-jacking involves criminals hijacking computers to “mine” digital currency. This can cause computer damage or outages, and spikes in electricity costs.

“Hacking humans is now big criminal business,” Head of Underwriting and Product Development Jeff Gonlin said. “People are the weakest link in the security chain.”

The Australian Competition and Consumer Commission’s Scamwatch data shows the number of business email compromise incidents increased 33% last year, accounting for 63% of reported business losses.

The watchdog is encouraging businesses to immediately review their processes for verifying and paying invoices.

“Social engineering scams can be sophisticated and many businesses only realise they’ve been caught when it’s too late,” Mr Gonlin said.