Federal Group executive general manager Dr Daniel Hanna said in a statement that the incident had taken place on 3 April.
Machines at Wrest Point in Hobart and the Country Club were affected, but were not closed, he said.
The Group also runs a number of hotels and the attack has affected booking systems at these outlets.
"The Australian Cyber Security Centre and relevant law enforcement agencies have been notified, and continued forensic analysis is being undertaken.
"Federal Group has at all times complied with legal and regulatory requirements related to the incident.
:The incident is being actively investigated by Federal Group and external experts we have retained, with the co-operation and involvement of relevant authorities who are assisting, and as such we cannot comment further at this stage.
"Our team has done an excellent job to ensure we have been able to continue serving customers and guests.
"Our company is one of many Australian businesses that have been impacted by increasingly sophisticated and complex incidents of this nature."