Ayman Guirguis
K&L Gates
1 O'Connell Street
Sydney, NSW 2000
Main Practice Area


  • LL.M., University of Sydney, 1999
  • LL.B., University of Sydney, 1987
  • Bachelor of Economics, University of Sydney, 1985

Mr. Guirguis advises clients on all aspects of antitrust/competition law as well as consumer law. 

Mr. Guirguis has a wealth of experience advising clients on merger clearance, joint ventures and on supply chain arrangements between suppliers and customers. 

Mr. Guirguis regularly advises on, and responds to, regulatory investigations by the Australian Competition & Consumer Commission (ACCC) alleging cartel conduct (price fixing, market sharing or bid rigging), including making immunity and leniency applications, competitor interactions at Industry Associations, as well as on other anti-competitive allegations such as misuse of market power, exclusivities, including defending litigation commenced by the ACCC. 

Mr. Guirguis also counsels clients on the Australian Consumer Law, including advertising and sales, marketing practices as well as compliance programs and audits. 

Mr. Guirguis has acted for clients across a range of industries including petroleum, oil and gas, property and construction, financial services, packaging, IT, retail, including food and fast moving consumer goods (FMCG) and pharmaceutical.

Professional Background

Prior to joining K&L Gates, Mr. Guirguis was a partner of two national Australian firms for a period of 16 years. He was also a senior officer in both the Mergers Branch and Enforcement branches of the ACCC.


  • Ranked as one of Australia's leading lawyers in Competition Law by Best Lawyers (2013 - 2020)
  • Listed in Chambers Asia Pacific for Competition/Antitrust, 2008 – 2019
  • Ayman Guirguis is "a highly regarded competition lawyer whose practice combines a number of sector-specific skills with broad competition expertise. A satisfied client reports: He gets to the point, is at the forefront of the industry and regulation and is always pre-empting issues for us in an unprompted way." (Chambers Asia Pacific 2019)
  • Ayman Guirguis is described as "very commercial and practical." (Legal 500 Asia Pacific 2019)
  • Ayman Guirguis is "well known in the market for his deep experience across all areas of Australian competition law. His dedication to his clients is also appreciated by interviewees, one of whom notes: Ayman is incredibly responsive and reliable and always makes you feel like your matter is top priority. He always goes out of his way to provide excellent service and to understand his client's business." (Chambers Asia Pacific 2018)
  • Ayman Guirguis is "easy to work with and showcases a commercial approach with great breadth and depth of knowledge." (Legal 500 Asia Pacific 2018)
  • Recognised in Regulatory Compliance and Investigations by Legal 500 Asia Pacific, 2018 – 2019
  • Recognised in Competition and Trade by Legal 500 Asia Pacific, 2018 – 2019
  • Listed in Global Competition Review’s Who’s Who Legal for Competition, 2012 – 2019
  • Listed in Legal 500 Asia Pacific for Competition and Trade, 2015 – 2017
  • Australian Non-Government Adviser representative of the International Competition Network, 2009 – 2017

Professional/Civic Activities

  • Law Council of Australia Competition and Consumer Law Committee member
  • American Bar Association member
  • International Bar Association member
  • Association of Corporate Counsel member
  • Law Society of New South Wales member
  • Additional Information
  • Mr. Guirguis has experience defending court actions by the ACCC and other market participants and advising on, setting up and implementing competition law and consumer law compliance programs. 


  • Mr. Guirguis has authored numerous articles on the areas of Competition and Antitrust Law, particularly regarding cartel conduct and the immunity process in Australia and the Australian Consumer Law.
  • Chapter 2 Australia, The Cartels and Leniency Review - Edition 3, January 2015
  • Chapter 1 - Australia, The Dominance & Monopolies Review, September 2014


  • Federal Court of Australia
  • High Court of Australia
  • Supreme Court of New South Wales
  • Supreme Court of Victoria
Practice Areas
  • Investigations, Enforcement and White Collar
  • Life Sciences
Client News