News reports indicate that interior portions of Papua New Guinea were ravaged by several landslides, which contributed to the damage of permanent buildings, as well as the screeching halt of oil and gas mining operations.
Earlier, Catholic priest Father Pius Hal told the Papua New Guinea Today website two children of a local government leader were among five killed by quake-triggered landslips in Mendi town.
Authorities said they expected more deaths in outlying villages.
Roads and rivers in the region were blocked by landslides and some buildings collapsed, Birisi said. The IRC's Regmi said communications were "completely down" in Tari, one of the larger settlements near the quake's epicentre, and that landslides had cut roads.
Rescuers in Papua New Guinea are trying to reach people buried in rubble after a 7.5 quake hit PNG's highlands region yesterday.
Aid agencies said they were ready to help but were also awaiting more information.
The Pacific Tsunami Warning Centre says there are no regional tsunami threats.
A 5.5 magnitude aftershock struck near Porgera, according to USGS.
Oil Search Managing Director Peter Botten said the company was closing down some production operations in the region as a precaution.
He said computer modelling for the original quake estimated significant casualties and over $US100 million worth of damage.
Earthquakes are common in the country, which sits on the Pacific's "Ring of Fire", an arc of seismic faults around the Pacific Ocean.
"It's premature to comment on what the impact to Porgera may be as those assessments remain underway.?The mine does have limited back up power generation available on site", Barrick Gold spokesman Andy Lloyd said in emailed comments.
The large natural disaster damaged buildings and caused landslides across the highlands, and powerful aftershocks have continued to rattle the region.