Local mayors are unhappy with the time it will take to replace the Manawatu Gorge road.
Four options have been unveiled, costing between $300 million and $450m, with each expected to take between five and seven years to build.
The highway has been shut since April, after it was deemed unsafe following a number of slips.
Tararua District mayor Tracey Collis said the replacement timeframe was double what she had been expecting and the council was now investigating how that would affect the community.
"We've currently got a social and economic analysis being undertaken to understand fully what the impacts of the closure of the gorge are," she said.
"There's a thousand less cars, so how will those businesses adapt to a six-year timeframe?"
Although the projected wait time was disappointing, officials had told her it was a realistic timeframe.
The four options are a new road north or south of Saddle Road, upgrading Saddle Road or a road south of the gorge.
Palmerston North mayor Grant Smith said construction time could be slashed to four years and the council was asking the Transport Agency and minister to look at a special fast-track option like Kaikōura's State Highway 1.
"Anybody that's in local government knows that this is quite a quick process."
Councils are expecting to know a final decision on the options in December.
Both mayors favour the route south of the Manawatu Gorge.
Ms Collis said she would also be open to a road across the Ruahine Range.