Walter Bau-AG has acquired about 43% of Ed Zublin AG's share capital, taking its total stake to more than 90%.
Walter Construction Group chief executive officer Michael Frick said the acquisition would help strengthen Walter's position in the Australian market.
"Walter's long-term growth and development strategies in Australia will see the ongoing involvement of our parent company, Walter Bau-AG," he said. "This will also allow us to draw on the expertise of the parent in selected markets and segments here in Australia."
Walter Bau-AG and Ed Züblin AG will retain their independent market presence in core markets. Stuttgart remains a key location and will be used as the new company's technology centre.