This is the biggest change to Australia’s merger laws in 50 years. Currently, Australia's merger laws do not require merger parties to notify the ACCC or wait for ACCC clearance. The changes to merger laws are relevant to businesses contemplating a merger, and also their competitors, suppliers and customers.
New merger laws commenced on a voluntary basis on 1 July 2025. They will commence on 1 January 2026, on a compulsory basis.
From 1 January 2026, acquirers must notify the ACCC about proposed mergers that exceed certain thresholds or fall into particular categories. These mergers will need ACCC approval before they can be completed: Competition and Consumer Act 2010 (Cth) ss 189, 51ABE, 45AY and Treasury Laws Amendment (Mergers and Acquisitions Reform) Act 2024 (Cth).
This is the biggest change to Australia’s merger laws in 50 years. Currently, Australia's merger laws do not require merger parties to notify the ACCC or wait for ACCC clearance. The changes to merger laws are relevant to businesses contemplating a merger, and also their competitors, suppliers and customers.
The ACCC will be the sole first instance administrative decision-maker for mergers. The ACCC must assess whether the acquisition is likely to substantially lessen competition or result in a public benefit. Merger parties will be able to seek a notification waiver from the ACCC. The ACCC must publish details of notified mergers on a public register.
The merger will be void if the merger parties purport to complete a notifiable merger without notifying the ACCC and obtaining the ACCC’s approval. The merger will also be void if the merger parties purport to complete it while a Tribunal review is ongoing, or if 12 months have elapsed since the ACCC’s approval.
Large acquirers and serial acquirers (including digital platforms, private equity, retail, industrial property and health, aged and child care businesses) are most likely to be impacted. The merger reform proposals are likely to enable the ACCC to block incremental acquisitions in concentrated markets, like digital platforms — particularly the change to the substantial lessening of competition test and the inclusion of past mergers into the thresholds.
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Our commentary covers:
- Sources — Links to commenced law, amending Act, Notification determination & guidelines etc (see below)
- Notifiable mergers
- Waivers
- Timelines & review
- Consequences for breaches
- Merger legal tests & change to the definition of “substantial lessening of competition”
- Notification forms
- Fees, acquisitions register and portal
- Transitional arrangements
- New law vs current law (and Bill vs draft Bill)
- Specific contexts: The new merger laws affect a wide range of industries and transactions (beyond what was previously considered a “merger”). Make sure you are not surprised or caught out! For example:
- Sales & leases of land
- Intellectual property rights
- Funds and investment platforms
- Charities.
Sources — Links to commenced law, amending Act, Determination and guidelines
Commenced law: Competition and Consumer Act 2010 (Cth), Part IVA (Notification of acquisitions), ss 45AY (Stayed acquisitions must not be put into effect), 50 (Prohibition of acquisitions that would result in a substantial lessening of competition), 51ABB (Acquisitions to which acquisitions provisions apply), 51ABE (When acquisitions are stayed), 51ABO (When acquisitions are required to be notified), 51ABP (Notification thresholds), 51ABW (Notifications of acquisitions), 51ABZH (Substantial lessening of competition), 189 (Requirement to notify from 1 January 2026).
Amending Act: The Treasury Laws Amendment (Mergers and Acquisitions Reform) Act 2024 (Cth) received assent on 10 December 2024. The key amendments commence on 1 January 2026 and commenced on 1 July 2025. Some supporting amendments commenced on 11 December 2024.
EM: The Explanatory Memorandum (EM) and Second reading speech shed light on the Treasury Laws Amendment (Mergers and Acquisitions Reform) Act 2024 (Cth).
Notification thresholds, Fees & Notification forms: The Competition and Consumer (Notification of Acquisitions) Determination 2025 (Cth) ("Notification determination") contains the merger notification thresholds, fees and forms. It is explained in the Replacement explanatory statement.
Waiver & control: The draft Competition and Consumer (Notification of Acquisitions) Amendment (2025 Measures No 1) Determination 2025 (Cth) details the notification waiver process and requires businesses to notify the ACCC about certain mergers even if they do not get control. Consultation on the draft Determination ended on 3 November 2025.
Wider exemptions: The Australian government will create new and wider exemptions from mandatory merger notification before 1 January 2026: Assistant Minister for Productivity, Competition, Charities and Treasury Dr Andrew Leigh MP, Refinements to exemptions proposed for new merger regime, 15 October 2025.
ACCC guidance:
- ACCC, Guidance on notifying acquisitions - When to use the long notification form, June 2025.
- ACCC, Interim merger process guidelines, 30 June 2025.
- ACCC, Merger assessment guidelines, 20 June 2025.
- ACCC, Frequently asked questions about merger reform, 11 November 2025.
- ACCC, Transition to a new merger control regime
- ACCC, Merger process quick guide for business, 1 July 2025.
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