The first section of the newly sealed and widened Carpentaria Hwy has been opened, seven months after the Fyles Government said it would be finished.

Infrastructure, Planning, and Logistics Minister Joel Bowden said in a statement the 48km section of the highway had been upgraded from single lane to dual lane bitumen, works which were part of a $150 million, three year project improving various sections along 138km of the highway.

The federal government is to pay for 80 per cent of the works and the Fyles Government, 20 per cent.

Ms Bowden said that section of the highway now provided year-round access, and the first stage also included widening, elevating and sealing the stretch, as well as installing 24 culverts so there would be less flooding, and creating two truck stops .

A $67 million contract was awarded to Exact Contracting in June last year with the government saying the works were expected to take 10 months. They instead took 17 months.

Mr Bowden did not say how much the upgrade ended up costing

Stage two, which will see upgrades from chainage 50km to chainage 140km, is also being undertaken by Exact Contracting, the minister said.

The Carpentaria Highway runs for 380km from near Daly Waters to Borroloola.