CountPlus has acquired a 30% stake in DMG Financial Holdings.
This takes CountPlus' network from 19 to 20 firms. Consideration for the investment is a cash payment of $2.891 million.
DMG Financial is an accounting and financial advice firm based in Gippsland.
CountPlus chief executive Matthew Rowe said: "The CountPlus 'Owner-Driver, Partner' model allows for businesses to retain their identity while simultaneously working with CountPlus to sustainably grow their businesses."
He added that the investment in DMG Financial is an example of that strategy in operation.
"The CountPlus model only allows for quality firms that meet the highest standards to join, and we are excited that DMG Financial will be joining our network," Rowe said.
DMG Financial managing principal Mathew Johns said: "CountPlus is a network that puts the client at the centre of everything, and that belief mirrors the DMG way of doing business."
"We very much look forward to continuing to provide a vital service for our clients in the Gippsland region, while availing of the strategic vision, resources and capabilities of the CountPlus network."
CountPlus has consistently indicated that it has plans to continue expansion.
"We are focused on realising our vision to become Australia's leading network of professional accounting and financial advice firms, aligned through shared values, mutual success and our sense of community. This investment in DMG is another encouraging step towards achieving our vision," Rowe said.
"Our growth strategy focuses on identifying suitable businesses to partner with through our extensive vetting program and ensuring that all CountPlus firms match the CountPlus family photograph."
He added that he believes the convergence of accounting and financial advice holds huge potential.