The first leg of the Woolgoolga to Ballina Pacific Highway upgrade will be put out to tender next week.

Detailed plans for the 125 kilometre, 5 billion dollar project have been completed, and contractors are now being sought for the stretch between Woolgoolga and Glenugie.

The State Government has given itself four-and-a-half years to complete the $5 billion, 125 kilometre project.

State Roads Minister Duncan Gay says despite significant delays in other parts of the project, the 2020 deadline can be met.

"We're mainly in an area of greenfields, and you move quicker in greenfields site," he said.

"The tender process that we're entering into will be a different kind of tender.

"I'm confident that 2020 is very achievable."

The Sapphire to Woolgoolga stretch of the Pacific Highway duplication, just north of Coffs Harbour, was officially opened this morning.

Mr Gay said that means all attention has now turned north to Ballina.

He said having federal funding locked in provides certainty for the duration of the project.

"The key is that we have is an undertaking from the Federal Government of 80/20 funding," he said.

"That means that we're not dealing day-to-day with political arguments, day-to-day with the begging bowl.

"We can actually get on, and work sensibly, and work sensibly to get the best tender and the best project to finish it."