Please note that the contact details for registering a Proxy and/or the Form of Registration with DnB NOR Bank ASA, TGS' Share Register manager, in the Notice of the Ordinary General Meeting 2009 issued on 1 May, 2009 were incorrect and should not be used.

The correct address and telefax number is:
DnB NOR Bank ASA, Verdipapirservice, Stranden 21, N-0021 Oslo, Norway.
Telefax: + 47 22 48 11 71

Registration may also be made via the company's websitehttp://www.tgsnopec.com/2009-AGM.aspx

The Proxy and Form of Registration have been updated on the TGS website and is also attached in English and Norwegian.

The ordinary General Meeting of TGS-NOPEC Geophysical Company ASA will be held on 4 June, 2009 at Shippingklubben, Haakon VII's gate 1, Oslo, at 16:00 hrs.

TGS apologizes for any inconvenience that this has caused.

Proxy and Form of Registration English

Proxy and Form of Registration Norwegian