The strong tremors hit a region already badly damaged by the magnitude 7.5 quake that struck on February 26, triggering landslides, flattening buildings and closing oil and gas operations. "Big trucks can not go there".
The death toll from the combined quakes has now risen to 67, said Udaya Regmi, the head of the Red Cross in Papua New Guinea, according to CNN.
"What we experienced this morning could have caused more damage, but we don't know ... it nearly threw me out of bed".
A report by the World Food Program for the United Nations two days after the quake estimated 465,000 people were exposed to the disaster of which 143,000 needed urgent humanitarian assistance and 64,000 were suffering from extreme food insecurity.
Last week's quake was one of the largest to hit the region in almost a century, triggering landslides, destroying buildings and disrupting communication lines.
While the region has no major urban centres, around 670,000 people live within 100 km (62 miles) of the epicentre, according to the Red Cross.
At least 13 people were killed when hamlets nearest the epicenter were buried.
Isaac Pulupe, a resident of Tari, in Hela Province, which bore the brunt of the quake, told Radio New Zealand that most buildings in his town of 10,000 had collapsed, including the school and part of the hospital.
ASX-listed energy explorers and producers Oil Search and Santos between them own 42.5 per cent of the ExxonMobil-led PNG LNG Project.
"We know at least 500 people are injured and 127,000 people need immediate aid such as food, water, shelter and healthcare" Regmi said.
Australia, New Zealand and the Red Cross have all pledged aid to help the recovery process.
Prime Minister Peter O'Neill declared that the closure of gas factory had a "huge impact" on the economy which relies on its natural resources.
"The initial response by our workforce, coupled with controlled emergency shutdown systems, safely shut in our facilities, minimising damage to equipment and ensuring there were no release of hydrocarbons", ExxonMobil PNG managing director Andrew Barry said.