The selection of a preferred option for a new permanent route to replace the Manawatu Gorge road has been put back, with the NZ Transport Agency saying more work is needed.
State Highway 3 through the gorge has been closed since April after large slips came down.
A shortlist of four options to replace it was unveiled in October with the preferred route scheduled to be named in December.
NZTA regional transport system manager Ross I'Anson says there has been good progress in assessing the options, but further discussions are needed with local councils and other stakeholders.
"It's vital we have strong support on the new route as it will represent a very significant long-term investment and it will need to serve the region and the country for decades to come," he said.
Mr I'Anson said the NZTA was now aiming to complete the assessment in the first quarter of 2018 and have the preferred option announced soon after.
The deferral was welcomed by local government and businesses, with Palmerston North Mayor Grant Smith saying his council supported the move.
Mr Smith said that, while confirming an alternative route as quickly as possible was important, the project was an opportunity to deliver more than just a traditional roading solution.
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