The earthquake measured 7.5 in magnitude in the Southern Highlands province around 560km northwest of the capital, Port Moresby.
The quake triggered landslides, damaged mining, gas and power infrastructure and cut communications. Scores of aftershocks were felt over the last few days, including one that measured 6.0 in magnitude, that hit on Wednesday just before 13:00 (around 05:00 SA time).
The aftershocks also hampered rescues efforts.
Initial reports did not indicate any casualties, but subsequent search and rescue efforts found that at least 20 people were killed. The majority were in or around Mendi, the provincial capital, and the town of Tari, Reuters reports.
Tari is around 40km from the epicentre. One person was confirmed to have died there, while another five were killed in a landslide in a nearby village.
The powerful 7.5 quake flattened whole villages and spoiled water sources.
“It’s massive destruction,” Stanley Mamu told Reuters telephonically from Tari.
“There are buildings on the ground and landslides along the roads. My home was destroyed. The main sources of water were all flooded, it’s dirty and brown and people can’t drink that water,” Mamu added.
Director of Risk Management at Papua New Guinea’s National Disaster Centre, Kaigabu Kamnanaya, explained that a cloud cover and afternoon fog hampered official efforts at assessing damage via helicopter.
A police officer in Mendi says that residents are living in fear of a nearby river flooding the town. He said that landslides had buried homes and blocked a river.
“We are really in deep fear,” police sergeant Naring Bongi told Reuters.
“It continues to be active. We didn’t sleep well and stayed awake until daybreak … no helicopters or government officials have come to our assistance.”
A spokesperson for provincial MP Manasseh Makiba, James Justin, explained that the country was in urgent need of medical supplies and heavy equipment to clear landslides.
“The casualties have yet to be confirmed but many more than 20 people have lost their lives,” he explained.
PNG is no stranger to earthquakes, as it is situated on the Pacific’s hotspot for seismic activity known as the “Ring of Fire”. Earthquakes are caused by the friction emanating between tectonic plates.
An earthquake in 1998, measuring 7.0, generated a tsunami that destroyed part of PNG’s northern coast and killed around 2 200 people.