Aid workers in quake-hit Papua New Guinea say road blocks from landslides and damage to telecommunication networks are hampering rescue efforts.
The Red Cross says at least 20 people are confirmed dead so far, and thousands more are in need of help.
Monday's 7.5-magnitude jolt, centred near Hela Province capital Tari, has transformed the mountainous Southern Highlands province, destroying homes and leaving locals digging through debris as they hunt for survivors.
One villager told Newshub the quake, which hit at 4am (local time), has taken everything.
"This landslide came and carried all the sweet potato, the houses, the pigs. A big disaster happened here."
Emergency coordinator Peter Wari says the damage is severe.
"Many properties have been lost."
Another densely populated area, Mendi, was also hit hard. Both areas remain cut-off.
Head of the International Federation of Red Cross Udaya Regmi says accessibility is the biggest challenge.
"The official death toll is expected to rise."
Hamilton man Rodney Kingi has lived in Papua New Guinea for seven years. He manages a truck transport company and says he's still trying to get staff out of affected areas.
"We've evacuated 40-odd guys out of one area and we are about to do another evacuation of another 25 guys out of another area."
He says aftershocks are still being felt.
"Every hour, every couple of hours... ranging between mid-fours up to the sixes.
"You get the odd earthquake here which can be aggressive, but nothing like what's happened now."
For the meantime, supplies will need to be airlifted to those in need. Key airports are not functional and helicopters remain just about the only way to get around.