Roading policy


The following policy was formulated in 2000 and amended in 2009. We have now seen the Draft Report and Decision of the Board of Inquiry into the Transmission Gully Motorway Project and stand by the policy.




The northern route from Wellington City to the Kapiti Coast via State Highway 1 can no longer adequately deal with daily traffic flows and the Government intends to increase traffic capacity through new road construction. Two alternatives are being proposed: extending the existing coastal route between Mana and Raumati and building an entirely new motorway through Transmission Gully.

Any upgrade of the coastal route will increase road traffic around the Inlet and require current roads, especially SH 1, SH 58 and Grays Road, to be upgraded. We oppose any such upgrading. Roading around the Inlet has already altered the natural character and ecological values of the Inlet and its margins and continues to provide increasingly adverse consequences for the Inlet’s ecological and recreational values. Further upgrading will lead to greater adverse effects. Grays Road in particular is located along a highly sensitive part of the estuary and upgrading this road, especially straightening it, will significantly degrade the ecological values of the entire Inlet.

The Transmission Gully Motorway (TGM) will be the main route from the Kapiti Coast to Porirua, Wellington and the Hutt Valley. It will direct traffic away from the immediate environs of the Inlet.

We believe that TGM has greater potential for reducing the negative impact of roads on the environment of the Inlet than the upgrading of the coastal route.

Roading Policy

The Guardians of Pauatahanui Inlet (GOPI) opposes the upgrading of the coastal route and supports the building of the Transmission Gully Motorway as soon as is possible.


Policy formulated March 2000, amended August 2009


Contact us

Please email your comments and questions about this policy or write to the Secretary, Guardians of Pauatahanui Inlet, PO Box 37034, Mana, Porirua 5247, New Zealand.


Read more about the reasons for our policy below. 

Inlet ecology

Roads ring much of the Inlet shoreline. These roads have considerably damaged the natural character and ecology of the Inlet. Large areas of salt marsh and adjoining freshwater wetland have been cut off from the Inlet and many of these areas have subsequently been drained. Wetlands (salt marsh and freshwater) are highly productive ecosystems and provide habitat for a wide variety of plant and animal species. They are also nursery areas for a number of fish species. The organic debris that results from natural death and decay of wetland plants directly or indirectly provides at least 60% of the food requirements of the estuarine fauna. The loss of wetlands around the Inlet margin over the years has had a significant impact on the ecology of the Inlet and an even greater impact on the Onepoto Arm of the harbour.

Much of this loss has been caused by the construction of road and rail transport corridors. Also, although there are no firm figures on the extent of their influence, there can be no doubt that they have altered the tidal flushing pattern of the harbour. This in turn is continuing to affect the distribution and extent of some intertidal sand banks. The construction of a second road bridge over the mouth of the Inlet is the latest structure built without adequate research or forethought as to its effect on the Inlet.


Run-off from roads

Storm water run-off from roads in the Inlet catchment is a source of pollution because it contains residues from oil and other spillages and from tyre and brake wear and incompletely burnt hydrocarbons. The current level is not yet critical, but is increasing and will continue to do so unless road run-off is contained or filtered before draining into the Inlet. The problem is worse from roads that border catchment streams and particularly from the heavily used SH 58 and Grays Road that run alongside the Inlet itself.


The safety of pedestrians and cyclists

The ever increasing volume of traffic on SH 58 and Grays Road poses potentially severe safety issues for pedestrians and cyclists and thus reduces the attractiveness of the Inlet as a place for recreation.


Environmental mitigation

TGM has the potential to adversely affect ecological values if adequate environmental safeguards are not put in place. The NZ Transport Agency (NZTA) recognises this risk and has already undertaken some mitigation measures by planting trees in the designated TGM area. NZTA's stated intention is to design a project that fully protects both the immediate environment and that of the Inlet.

Last Updated: 14/12/2015 12:00am