May 12 (Reuters) - Australia's TechnologyOne Ltd said on Friday its customer-facing software-as-a-service platform was not connected to the internal back-office system that came under cyber attack this week.

The software maker said on Wednesday it had detected an unauthorised third-party access to its internal Microsoft 365 back office system, making the company the latest target in the wave of cyber attacks that has plagued multiple firms since last year.

The company reaffirmed that the internal back-office system, which was isolated to contain the spread of the incident has been restored and is fully operational.

TechnologyOne said third-party cyber security experts have confirmed that its systems are secure and there has been no further illegal activity detected.

"Our focus remains on the investigation into the incident to determine what data may have been accessed via our internal Microsoft 365 back-office system, and then as is necessary, to engage with impacted individuals on appropriate actions," the company said in a statement.

Major companies such as grocer Woolworths, telecoms Telstra and TPG Telecom have reported data breaches and unauthorised access, bringing to light corporate vulnerability to cyber attacks.

(Reporting by Archishma Iyer in Bengaluru; Editing by Sherry Jacob-Phillips)