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Peter Mantas Ottawa Lawyer

Peter N. Mantas

Partner Fasken
In an increasingly complex business world, the risk of running afoul of the law, both at home and abroad, cannot be underestimated.
Jurisdiction New York, 1993 | Ontario, 1994
Office(s) Ottawa, Toronto, London


Peter Mantas is a senior litigation partner frequently retained to act in complicated, high stakes matters, including those of national and international importance. Clients appreciate Peter’s experience, strategic advice, knowledge, and tough but reasonable approach. He is also valued for his skills in crisis management, reputational risk and media relations.
Peter is the leader of Fasken’s Procurement group, co-leader of its White Collar Defence and Investigations group, and leader of its Ottawa Litigation group. Peter has experience in matters involving government, international trade and business, procurement, mining, tech, media, Indigenous affairs and competition. His knowledge covers corporate/commercial, administrative/public and criminal law cases.  He has been involved in numerous investigations, trials, appeals, administrative/tribunal hearings, and domestic and international arbitrations.  
Peter has been repeatedly recognized by Chambers, Benchmark Litigation, Legal 500, Who’s Who Legal and Best Lawyers in Canada.  A member of the Bars of New York and Ontario, in 2020 he was inducted as a Fellow into the Litigation Counsel of America. Peter has been nominated in Canadian Lawyer magazine as one of the 25 most influential lawyers in Canada.
Peter has worked on the following notable cases:


  • Counsel to the Assembly of First Nations and others in the largest class action in Canadian history. Also known as the Millennial Scoop, the case involves the federal government’s role in the forced removal of Indigenous children from their families and the systemic discrimination against these children. The government has set aside $40 billion in relation to the case, which is currently in settlement negotiations.
  • Counsel to Panthera Resources and Indo-Gold in relation to the expropriation of the Bhukia Mine project in India. Case involves rights arising under the Australian-Indian Bilateral Investment Treaty (BIT).
  • Lead counsel for Fasken team appointed by the UK government to its panel of law firms in relation to post-Brexit international trade disputes.
  • Counsel to Tenke Fungurume Mining SA in relation to a commercial dispute involving a construction project at its operation in the Democratic Republic of Congo. Case proceeded by arbitration, with a virtual hearing before the International Commercial Court (ICC), under English law and with the seat of arbitration in London.
  • Counsel to Export Development Canada (EDC) in relation to a cross border commercial dispute before the courts of Ontario and New York. Case is with regards to a significant railcar financing matter with Amtrak and the Phillip Morris Corporation.  
  • Counsel to the Conservative Party of Canada to defend its decision to disqualify a candidate from the party leadership race for posting racist comments on social media. Case was one of the first major virtual hearings by a Canadian court during the pandemic. Candidate remained disqualified.
  • Counsel to Rogers Communications with respect to a commercial arbitration dispute against Iristel. Case involved matters related to findings in a separate decision by the CRTC addressing the issue of traffic pumping. 
  • Counsel to Alion against the federal government to challenge an award of the largest procurement in Canadian history (over $60 billion) in relation to the replacement of Canada’s naval frigates and destroyers. 
  • Counsel to President of the Treasury Board and Cabinet Minister Scott Brison in relation to the leak of Cabinet secrets in the R. v. Admiral Mark Norman case.
  • Counsel to Rogers, Bell and Quebecor with respect to the collection of ringtone royalties by SOCAN.
  • Counsel to Ethnic Channels Group (ECG) in an international broadcasting rights and contract dispute between ECG USA and Moscow based CTC Media. An action was commenced in Ontario and negotiations occurred in London.
  • Counsel to Thales before the Canadian International Trade Tribunal (CITT) in a procurement challenge relating to a major defence contract involving battleground technology.
  • Counsel to KPMG in relation to an international commercial dispute against Canadian Water Projects involving litigation in Ontario and negotiations in London.
  • Counsel to TPG Consulting in an 8-month criminal jury trial for alleged bid rigging and fraud in relation to IT services to the federal government. TPG, and all other accused including TPG executives, were acquitted.
  • Counsel to Odyssey TV regarding Internet and broadcasting piracy by Ellas TV. Case resulted in one of the largest monetary awards for breach of copyright in Canadian history.
  • Counsel to the Rockstar Consortium (Apple, Blackberry, Ericsson, Microsoft and Sony) regarding the protection of confidential information in relation to the global Nortel pension litigation.
  • Counsel to former Chief of Staff to the Prime Minister, Nigel Wright, in the case of R. v. Senator Duffy.
  • Counsel to the Prime Minister of Canada and others with respect to the removal of former Cabinet Minister Helena Guergis from her position in Cabinet and caucus.


Client Work

Date Client

Career & Education


  • LLB University of Ottawa
  • BA, Trinity College University of Toronto

Community involvement

Memberships & Affiliations

  • Fellow, Litigation Counsel of America
  • Co-Chair, Class Actions Section, Ontario Bar Association (2015-16)
  • Member, Canadian Bar Association
  • Member, American Bar Association
  • Member, Country of Carleton Law Association


Fasken Institute



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Speaking Engagements

Speaker Government Procurement in the EU CETA Business Summit location location Ottawa, ON
Speaker Putting CETA to Work for Canadian Business Toronto Region Board of Trade location location Toronto, ON


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