The federal government is working to find out whether a massive global malware attack has affected any Australian organisations.
Computer systems at companies and hospitals across the world were attacked on Friday, apparently part of an extortion plot.
There are no confirmed reports Australian organisations have been hit.
"We are continuing to monitor the situation closely and stand ready to deal with any cyber-security threat to Australia's critical infrastructure," Prime Minister Malcolm Turnbull said through a spokesman today.
The prime minister's right-hand man on cyber security, Alastair MacGibbon, is working with officials and health agencies to determine any impact on Australia.
The attack struck at least 16 British National Health Service organisations, along with computer networks of companies and municipalities in dozens of other countries.
Several hospitals in London and other parts of England and Scotland were affected by the so-called ransomware, which blocks access to computer systems and asks for money to unlock it.
"It's an international attack and a number of countries and organisations have been affected," British Prime Minister Theresa May said.
More than 75,000 similar attacks have reportedly happened in 99 countries, with Russia, Ukraine and Taiwan hardest hit, according to the cybersecurity firm Avast.
Several NHS computer systems, including telephones, were crippled, causing delays at some hospitals amid fears the lives of patients were at risk.
Companies such Spain's telco giant Telefonica and US parcel delivery firm FedEx were among affected businesses.
The ransomware known as Wanna Decryptor is believed to be responsible.