The country's largest ISP was offline for most of the morning following a failure in its user login authentication system.
Xtra spokesman Matt Bostwick says the issue lasted from 7am until around 9am.
"People would have been experiencing some delays in getting authentication," says Bostwick. All dial-up, JetStart and JetStream customers were affected countrywide.
"Some people were able to log on but it was fairly sporadic."
Bostwick says technicians are still investigating the cause of the problem, however it appears to have been "an issue with authentication at a radius proxy".