From www.russellkennedy.com.au: The ACCC has released guidelines for the new merger regime, which will come into effect on January 1, 2026, with voluntary use starting July 1, 2025.

Under the new rules, certain acquisitions must be notified to the ACCC and cannot proceed without explicit clearance, marking a shift from the current voluntary approach to a mandatory approval system.

During the transition period, businesses can still use the existing informal review process, but applications for merger authorization will be closed after June 30, 2025.