The Cyber Army may have been confused about who it had targeted - the group said it had hacked "The University of the Australian" in a Facebook message posted on Friday night.
The group has a history of hacking relatively low-traffic websites.
Previous targets included an Arkansas school district website and the website of a community in Quebec with a population of less than 2000 people.
An Auckland University spokeswoman said the English Language Academy (ELA) acted swiftly once alerted to the hack.
"The ELA website was hacked over the weekend and as soon as ELA was alerted, the site was taken offline and replaced with a maintenance page."
The website was hosted on a third party server and students should not be concerned about privacy, the spokeswoman said.
"No student data is stored on the server and no data was compromised."