Amsterdam: +31 20 737 20 66
Almelo: +31 546 89 82 46
Leeuwarden: +31 20 236 10 24

Derek Sietses

Derek Sietses is a partner of ENVIR Advocaten. Derek’s expertise covers administrative law, including environmental law, EHS matters and nature conservation law, as well as civil law, including contracts liability matters.

Derek has extensive experience in complex, politically sensitive cases, both representing local authorities, including municipalities, provinces and enforcement agencies, and companies and developers. In particular, Derek assists both government bodies and developers in various wind and solar projects on questions relating to contracting, permitting, civil law aspects and municipal taxes.

Derek is practical and efficient and brings a strategic and commercial approach to the table when assisting his clients. He is therefore well-placed to help his clients successfully navigate the complex legal context in which they operate.

Prior to joining ENVIR Advocaten in 2019, Derek worked for Stibbe Amsterdam in the administrative law and litigation department and at Trip Advocaten en Notarissen in Leeuwarden in the administrative law department. Derek regularly publishes in Dutch scientific and professional journals and gives lectures on various legal topics for a wide range of audiences. Derek heads ENVIR Advocaten’s Leeuwarden office.

mr. D. (Derek) Sietses
Romkeslaan 59 8933 AR Leeuwarden

T +31 20 236 10 24

M +31 6 1588 6936

F +31 20 796 92 22

What the team is known for: Broad industry knowledge representing private sector clients from the energy field, as well as public sector clients such as municipalities and provinces. Noted for its extensive expertise of nature protection and conservation matters. Also represents clients in sensitive disputes concerning permits and developments. Has expanded the team with several new hires during 2019.

Chambers, 2020

Marieke Kaajan represents clients in compensation disputes arising from construction projects, and also advises on environmental and pollution matters. Interviewees also report: ‘She is very well respected when it comes to nature conservation law.’

Chambers, 2020

One client appreciates the team’s ‘good tactical approach,’ further adding: ‘The lawyers were very pragmatic and helped us find solutions.’

Chambers, 2020

‘The team is very experienced, hands on and understands the business needs of the client and translate that into practical advice’.

Legal 500 – EMEA 2020

‘Iris Kieft is very knowledgeable on sustainability; speaks the language of the client and understands the client’s business’.

Legal 500 – EMEA 2020

Fleur Onrust is skilled at handling administrative law issues and environmental matters. Additionally she represents clients in sensitive litigation and advises on nature conservation.

Chambers, 2020

‘At ENVIR they combine the quality services of a top tier firm with the personal attention of the partners of a boutique firm’.

Legal 500 – EMEA 2020