The company said both guests who have stayed at Meriton suites as well as past and present employees could have been affected by the hack.
It said it has already notified the 1,889 people potentially involved after the incident on January 14.
It said while 35.6GB of data was potentially affected it claimed “very little was sensitive information”.
No credit card details or other guest data was taken, it said.
It said none of the data has been released and the incident was reported to the Australian Cyber Security Centre and the Office of the Australian Information Commissioner.
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“There is no evidence that affected individuals have had their information misused, nor that any information has been released into the public realm,” Meriton said.
“Meriton has been working closely alongside leading cyber-security and forensic IT professionals, and taking all available steps to protect against future risk to data and prevent recurrence.
“This has included implementing enhanced cyber security measures to protect Meriton’s network as well as extensive network monitoring so that Meriton can quickly identify and respond to any future issues.”
The company has multiple Meriton Suite apartments in Sydney, Brisbane and the Gold Coast, and one in each of Melbourne and Canberra.