Papua New Guinea police are investigating this weekend's fatal head-on truck crash.
The police say 16 people died instantly when two trucks carrying about 60 people in total collided on the main highway near Bereina in Central Province.
According to local media reports, a young boy has also since died from severe internal injuries, while several others are in a critical condition in hospital.
A police spokesperson, Dominic Kakas, says debris from a landslip seems to have triggered the accident.
"There was a landslip which filled up half of the road and both trucks seem to have come with a high speed from either direction. One tried to avoid the landslip and went into the line of the oncoming vehicle. There was an impact then."
Dominic Kakas says the earth from the landslip is still blocking the highway, but the road has re-opened for traffic.