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Sean O'Sullivan

Newcastle Managing Partner


+61 2 4911 5433 +61 409 589 805

Sean is a senior adjudicator under security of payment legislation in seven of Australia’s States and Territories, and has acted in more than 300 adjudications with amounts in dispute up to $100 million. His engineering and construction background coupled with his legal experience enables Sean to quickly understand the key issues and difficulties affecting clients.


As a leading construction lawyer and heading Moray & Agnew’s construction & infrastructure practice, he has significant experience in the resolution of security of payment and construction disputes through adjudication, litigation, arbitration, expert determination and mediation.

Sean has acted in many construction and building actions involving allegations of defective work, professional negligence and home owners’ warranty claims for and against contractors, owners and owners corporations.

Sean has acted in some of Australia’s seminal cases in the High Court of Australia and the Supreme Courts and Appellant Courts of NSW and Queensland, including:

  • Probuild Constructions (Aust) Pty Ltd v Shade Systems Pty Ltd (2018) 264 CLR 1
  • Mt Lewis Estate Pty Ltd v Metricon Homes Pty Ltd [2017] NSWSC 1121
  • Lahey Constructions Pty Ltd v Trident Civil Contracting Pty Ltd [2013] NSWSC 176
  • Clyde Bergemann v Varley Power [2011] NSWSC 1039
  • Chase Oyster Bar Pty Limited v Hamo Industries Pty Ltd [2010] 78 NSWLR 393 
  • Dualcorp Pty Ltd v Remo Constructions Pty Ltd (unreported, District Court of New South Wales, Quirk DCJ, 10 March 2009)
  • Brewarrina Shire Council v Beckhaus Civil Pty Ltd [2003] 56 NSWLR 576.

He has been appointed as mediator to resolve disputes between litigants in a number of NSW District Court cases.

Sean is admitted to practise in the Supreme Court of NSW and the High Court of Australia.

Prior to becoming a lawyer, Sean gained extensive project management and contract administration experience from 10 years working as a project engineer, construction manager and project manager for BHP and a NSW state-owned corporation on a host of multi-billion dollar and strategically significant projects through Australia and New Zealand.



Ranked in the peer-reviewed Best Lawyers® in Australia list for Alternative Dispute Resolution since 2024



  • Masters of Business Administration, 1998, Deakin University
  • Bachelor of Laws (Hons), 2003, Macquarie University
  • Bachelor of Engineering (Civil), 1992, University of Newcastle


    • NSW Certified adjudicator, Building and Construction Industry Security of Payment Act 1999 (NSW)
    • Qld Registered Adjudicator, Building Industry Fairness (Security of Payment) Act 2017 (Qld) 
    • Vic Certified adjudicator, Building and Construction Industry Security of Payment Act 2002 (Vic)
    • WA Registered Adjudicator, Construction Contacts Act 2004 (WA)
    • ACT Certified adjudicator, Building and Construction Industry (Security of Payment) Act 2009 (ACT)
    • SA Certified adjudicator, Building and Construction Industry Payments Act 2009 (SA)
    • Tas Certified adjudicator, Building and Construction Industry Security of Payment Act 2009 (Tas)


    • Business Hunter
    • Civil Contractors Federation (NSW)
    • Law Society of NSW
    • National Precast Concrete Association Australia
    • Property Council of Australia
    • Urban Development Institute of Australia (NSW)