The Economic Development Ministry unit says that the New Plymouth-headquartered STOS expects to also offer tender packages for onshore facilities, which will also include a processing plant and pipelines, on the coast.

Crown Minerals says STOS has sent enquiries to all the recognised engineering, procurement, construction and installation players in Australia and New Zealand, and also to Petroleum Technical Services Company of Vietnam, the turnkey contractor subsidiary of government-owned PetroVietnam.

STOS is seeking the most cost-effective bid for construction work, and is hoping that construction in New Zealand will be competitive.

Taranaki-based Transfield Worley, which has been involved in the front-end engineering and design work for Pohokura, has extensive oil and gas construction experience. However, some aspects of the work, such as pipelines, may well stretch the capabilities of the New Zealand engineering sector.

Two unmanned wellhead platforms will be required to extract gas and condensate from the Pohokura field, which lies from 2-14km off the north Taranaki coast.

A production pipeline, of up to 20 inches in diameter, and a 10-inch gas cycling pipeline will be laid on or under the seabed linking the platforms to an onshore production station at Motunui. Piggy back lines supplying services to the platforms will also be needed.

STOS - which is running the $US520 million project on behalf of Shell New Zealand, Todd Energy and OMV Petroleum - is likely to issue invitations to tender for the offshore packages after examining the potential bidders' expressions of interest.

First gas from Pohokura is scheduled ashore by early to mid-2006.