Kapiti Coast District Council is to consider whether to fight the Sandhills expressway project.
The new four-lane highway would stretch from MacKays Crossing to Peka Peka as part of the State Highway One northern corridor to Wellington. It will cost up to $500 million.
Kapiti Mayor Jenny Rowan wanted the existing SH1 widened to four lanes, and the existing western link, known as "Sandhills", to stay as two lanes.
She says she's extremely disappointed with the Government's choice, but won't be drawn on the possibility of trying to overturn the plan in whole or in part.
The council will consider its next move in February.