The company is part of the Nexia International Group that reported recenue of about US$4.3 billion ($A5.9 billion) in 2019.
The attackers claim to have stolen 76GB of data during the incident which took place recently.
iTWire contacted the company on Saturday, seeking a reply by Monday. The company has not responded to date.
A screenshot from the REvil website showing data from Nexia. Supplied
No data has been posted online as yet, indicating that the criminals may be waiting for the company to act on the ransom note which is normally generated after an attack of this nature.
REvil, which is also known as Sodinokibi, has been used in many attacks this year. It was used to hit the publicly listed US transportation services firm Matson, big casino supplier Gaming Partners International Corporation, Meinhardt Group, an engineering consultancy with 51 offices worldwide and 5000 employees, American IT staffing company Artech Information Systems, and publicly traded professional distribution management firm DXP Enterprises.
Others to suffer were Adif, an infrastructure company owned by the Spanish Government, Argentina's biggest Internet service provider Telecom Argentina, leading retirement specialist Actuaries and Associates, the website of Cooke County in Texas, and Australian drinks manufacturer Lion.
Melbourne-based contract formulation and packing company Chem Pack, New York-based entertainment and media lawyers Grubman Shire Meiselas & Sacks, Sydney sports specialty store chain Instore, American food distribution firm Harvest/Sherwood Food Distributors, SeaChange, a global public supplier of video delivery software, and Melbourne-based government-accredited IT services provider Geidi were all hit by gangs using REvil as well.