Professional Staff




Associate Attorney

Antonie Heyneke

Antonie holds a National Diploma in Electrical Engineering from the Vaal University of Technology and a LLB Degree through UNISA.

After pursuing a career in industrial electronics and specialising in various engineering industries he turned his attention to studying law.

He obtained his LLB Degree in 2017 and completed the School of Legal Practice at UP.  After completing his articles at HW Theron Inc., he was admitted as a Legal Practitioner in 2019.

He joined Hahn & Hahn in 2019 as a Practising Attorney and assists Ms. Everts in her department.

  • Civil Litigation
  • Collections
  • Family Law

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Associate Attorney

Madelein Kleyn

Madelein is a Chemical Engineer, an admitted attorney of the High Court of South Africa and a South African patent attorney. She has more than 27 years’ experience as in-house corporate Intellectual Property Counsel, in both Petrochemical and agriculture industries for international companies. She is an Expert Consultant to  Hahn & Hahn focussing on IP due diligence in support of merger and acquisition transactions, commercial technology related contracts inclusive of intellectual property licensing, exchange control advice and approval application for export of intellectual property in off shore corporate structures.  She also advises clients on IP strategy and policy development and implementation.

She holds a B.Sc. Eng. (Chemical), B.Proc, LLB, LLM (tax); PhD (Intellectual Property). She is a member of SARIMA, AUTM, INTA, SAIIPL, ACS, CCASA and LES (Past President).

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Associate Attorney

Merilynn Du Plessis

Innovative and driven Attorney with more than a total of five-year legal experience in private practice (five years of pre-admission and just over two years post admission). Proficient in legal opinion, research and studying different areas of law. Experience and passion for in training, research and communication. Thrives in dynamic environments and adapts to suit the ever-changing demands of the legal field. Strong ethical and relational compass. Respectful and attentive to diverse cultures and customs. Analytical mindset tackles legal problems with diligence, organization and completeness. Ability to execute and complete tasks and goals under high amounts of pressure. Conscious and intuitive of international developments and possess a passion to contribute to areas of need and upliftment.

  • High Court and Magistrates Court Litigation
  • Electricity Disputes
  • Construction law
  • Drafting opinions
  • Drafting Policies
  • Labour Law
  • Commercial Law
  • Miscellaneous Legal Practitioner duties


Candidate Attorney

Isabella Mazzone

Isabella holds a LLB Degree from the University of Pretoria and is currently a Candidate Attorney under the guidance of Janusz Luterek.

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Associate Attorney

Janet Tomkow-Coetzer

Janet holds degrees in Biotechnology and Law. She is an admitted attorney and is involved with Consumer and Food Law and deals with legislative issues around food and consumer protection, labelling of food products, product liability, resolution of disputes in the supply chain as well as technology law in general.

Janet is also involved in litigation of patents as well as patent applications throughout Africa

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218 Richard Street, Hatfield, Pretoria,
Tel: +27 12 431 2480 / 086 099 5130
Fax: +27 12 430 2103 / 086 632 4284