Trucking firms are suffering heavy losses, and the giant Porgera gold mine and Kutubu oil project face fuel shortages after traffic was disrupted on the Highlands Highway this week.
According to the authority, fuel and supplies bound for the Highlands provinces were held up in Goroka, while coffee and tea bound for international destinations missed their ships docked in Lae as the trucks were held up in Mt Hagen for a week.
Trucks have been pulled off the road and left waiting for the relevant authorities to repair the damaged sections of the highway and deal with landowner issues.
The National reports a creek in Simbu flooded last week and washed away a section of the highway creating a 20 meter deep gully.
Landowners claim the situation could have been avoided had authorities responded quickly to their earlier pleas, and say they would only allow the road to be fixed, after they are paid compensation.