A local leader, Wako Napasu told Loop PNG a landslide occurred on Saturday during heavy rains in the area.
Napasu and local elders fear that if nothing is done within the next 48 hours, the road will collapse.
He said the affected section of the road is two kilometres from Nebilyer bridge and 8 kilometres from Tambul government station
If the road collapses, this will impact the multimillion kina ADB funded construction work along the highway by contactor COVEC and subcontractor Makara Constructions.
Napasu says the livelihood of the population will also be affected because access to markers in Mt Hagen to sell farm produce will be affected.
Schools and government services will also be affected.
The provincial works department is yet to inspect the site, while travellers have resorted to forming a one lane road through the affected part of the highway.