Promised roading projects could be scaled back or dropped entirely due to significantly higher than forecast costs.

The government's infrastructure package, announced in January last year, included 5.3 billion dollars towards new and upgrades of roads across the country.

But Stuff reports it's in danger of collapsing, which could impact projects like Auckland's Mill Road, or Wellington's Otaki to north of Levin.

Infrastructure consultant Barney Irvine told Mike Hosking it's a classic example of what you get when projects are guided by political factors.

"Ahead of really robust analysis based on what the public need is and what the customers, the people who are paying for it really need."

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