Web host NetRegistry has been hit by a distributed denial-of-service attack that caused outages across its hosting and VPS cloud services.
The outages began around 10.15am AEST, according to users who converged on Twitter and internet forums seeking help from the service provider.
Services were mostly restored about an hour later. Only the Zeus cluster suffered "intermittent" issues until about 1.20pm.
The company said earlier in a tweet that an undisclosed “network issue” was affecting services and that technicians were addressing it “as the highest priority”.
It later clarified to say the cause was a DDoS attack.
"DDoS related issue. Coming in waves. Working with upstream providers to kill traffic," the company said.
NetRegistry's phone system had been “overloaded”. The company advised customers to email for support.
No data had been lost, the company said.
It was unclear whether NetRegistry directly or one of its customers was the target of the attack. A spokesman for NetRegistry has been contacted for comment.
Last year, NetRegistry suffered outages after Anonymous targeted the website of one of its customers, the Australian Federation Against Copyright Theft (AFACT), with a DDoS attack.