Admitted to the Bar 2010
Experience
Greg O’Mahoney practices nationally in all areas of commercial, corporations, regulatory, transport and aviation, competition, corporate crime, maritime, banking, insolvency, consumer, sports and public law. He undertakes trial and appellate work in State and Federal Courts and tribunals throughout Australia.
He is listed in the Legal 500 Guide as a tier 1 leading Commercial Disputes junior (2022, 2023, 2024 and 2025) and as a tier 1 leading Regulatory and White-Collar Crime junior (2022, 2023, 2024 and 2025). He is listed in the Doyle’s Guide as a leading Transport Law junior (2023, 2024 and 2025). He has been listed in the Doyle’s Guide as a leading Taxation Law junior in multiple years.
Greg appears widely in public inquiries across Australia, including corruption inquiries, Royal Commissions and coronial inquests. He has appeared in over twelve ICAC inquiries, including four as Counsel Assisting. He appeared for the NT Government in the Royal Commission into the Detention and Protection of Children, Carnival/Princess Cruises in the Special Commission of Inquiry into the Ruby Princess, and Airbus in the IGADF Inquiry into the crash of an MRH90 helicopter off Lindeman Island. He is a member of the NSW Bar Association’s Inquests and Inquiries Committee.
Prior to coming to the Bar, Greg was Associate to the Hon Murray Gleeson A.C., Chief Justice of Australia, and worked as a solicitor in litigation and arbitration at Mallesons Stephen Jacques.
He was awarded a Rhodes Scholarship to study at the University of Oxford, where he graduated with a BCL (First Class Honours) and a DPhil in Law. During his BCL year, he was awarded the Ralph Chiles CBE Prize for Comparative Human Rights.
He is a graduate of the University of Sydney, where he was awarded First Class Honours in Law and Arts (English literature). During his time studying at Sydney University, he won the World Universities’ Debating Championships in Glasgow.
Greg has taught corporations and contract law at Sydney University and Oxford University. He has established and taught a Masters course at Sydney University on the regulation of securities markets and white-collar crime.
At Sydney University, Greg won the University tennis championships and was captain of the tennis club across a number of years. He played in the Oxford University tennis team and was captain of the Magdalen College Tennis Team that won the Oxford Cuppers Tennis Championships for the first time in 76 years.
Principal Areas of Practice
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Commercial Law
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- Administrative Law
- Admiralty and Maritime
- Alternative Dispute Resolution
- Appellate
- Arbitration
- Aviation and Transportation Law
- Banking and Financial Services
- Bankruptcy and Insolvency
- Building, Construction and Technology
- Class Actions
- Communications
- Competition and Consumer
- Conflict of Laws
- Contracts
- Corporations and Securities
- Cross-border Insolvency
- Cryptocurrency
- Cybersecurity
- Environment and Planning
- Insurance and Reinsurance
- Intellectual Property
- International Law
- Mining resources and energy
- Partnership disputes
- Product liability
- Professional liability
- Real property
- Restraint of trade
- Shareholder class actions
- Sports law
- Superannuation
- Trade Practices
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Common Law
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- Alternative Dispute Resolution
- Appellate
- Class Actions
- Defamation
- Insurance and Reinsurance
- Medical negligence
- Personal Injury
- Product liability
- Professional indemnity
- Professional liability
- Sports law
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Criminal
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- Appellate
- Fraud
- Proceeds of crime
- White collar and corporate crime
- Work health and safety
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Equity
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- Alternative Dispute Resolution
- Appellate
- Property
- Trusts
- Wills and Estates
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Industrial/Employment
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- Civil and Human Rights
- Disciplinary Proceedings
- Government Inquiries
- Health Law
- Restraint of trade
- Work, Health and Safety Prosecutions
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Inquests and Inquiries
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- Commissions of Inquiry
- Coronial Inquests
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Public and Administrative Law
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- Alternative Dispute Resolution
- Appellate
- Constitutional Law
- Disciplinary Proceedings
- Health Law
- Judicial review and administrative law
- Merits review
- Native title
- Proceeds of crime
- Public law
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Taxation and Revenue
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- Alternative Dispute Resolution
- Appellate
- Capital gains tax
- Goods and services tax
- Income tax
- International tax
- Land tax
- Payroll tax
- Stamp duty and other state taxes
Sectors
Agribusiness, Banks & Financial Services, Defence, Funds, Government, Healthcare, Industrials, Transport and Infrastructure, Primary Resources, Power & Utilities, Real Estate, Technology, Media & Telecommunications,