The Transport Agency is taking over nearly all the country's bitumen supply vital to road building because it believes it is being ripped off by suppliers.
Documents show the agency warning that if it doesn't, the country overpaying in the $100m a year bitumen market will get worse.
The agency denied to RNZ that it even has a plan, but Z Energy is already telling customers it will stop importing bitumen from July 2023 because NZTA's move will leave it no room to operate.
Phil Pennington spoke to Susie Ferguson.