Gunnedah shire mayor Jamie Chaffey said work on the gravel thoroughfare was six months ahead of schedule and should be completed by late September.

The $8.2 million upgrade between Mullaley and Goolhi, and Goolhi and Boggabri is more than a decade in the making and was started in late 2018 in response to safety concerns for locals and travellers.

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Cr Chaffey said the council had added a second crew to the project a few months ago to speed things up.

"We've been pushing hard to get it ready for harvest," he said.

Cr Chaffey met Parkes MP Mark Coulton on the road on Friday so he could see the progress for himself. The last time the MP visited was in 2018 with Deputy Prime Minister and Minister for Infrastructure and Transport, Michael McCormack.

"When I was last here, the paddocks were brown and the road was gravel. Now there are green crops instead of dust and tar instead of gravel," he said.

Only 5km of the 17.6km stretch are yet to be tarred. The Mullaley to Goolhi section is complete and about 2km of the Goolhi to Boggabri section is now sealed.

Line marking will be done on the completed sections.

When the work is finished, Heavy Mass Limit (HML) vehicles will be able to use the road to travel from Mullaley to Boggabri. The route is currently General Mass Limited (GML).

The project is funded by the local, state and federal governments.