The privately-owned firm Integral Technology has bought Axon Computer Systems for an estimated $18 million.
Integral executive chairman David Sutherland says the combined entity has sales of about $150 million a year and about 360 employees.
Mr Sutherland says he expects the new company will be able to achieve faster growth, as Integral and Axon complement each other.
Staff from both companies will form the new management team, with Integral's managing director Ray Noonan retaining that role, and Axons' chief executive Scott Green becoming an adviser to the board.
The company name and brand is yet to be decided.