Guard Dog Security reported to the Lae Chamber of Commerce and Industry that the massive landslide struck at Kerowagi and even washed a double classroom from Kondiu High School into the Waghi River.
LCCI predicted supply chain impacts to the highlands on Monday.
"Obviously this will pose a real problem to heavy vehicles, that will not be able to get through to Mt Hagen and beyond at the moment, and in all likelihood for some time," LCCI said.
The National reported this morning that there were enough rice supplies in Mt Hagen for about a month and enough flour stocks for three weeks, but that it was unknown how much fuel was available.
"Everybody in the region is keeping their fingers crossed now waiting for the road to be re-opened as soon as possible," Mt Hagen-based Coca-Cola Amatil regional manager Chris Harker reportedly told the newspaper.