Australian operations are being left wide-open to cyber attack by ageing computer systems that have not been upgraded, cyber security experts have warned, as the Morrison government seeks to push through tougher digital security standards for critical infrastructure.

Despite Australia and New Zealand chief executive Shayne Elliott last week claiming that big businesses have largely addressed the problem of cyber security, George Kurtz, chief executive of NASDAQ -listed cyber security firm CrowdStrike, said hard and realistic conversations were needed across business and government about how to protect critical infrastructure from ransomware.