The magnitude seven quake struck at a depth of 85 kilometres near the border of Morobe and Oro provinces, off the north coast of New Guinea.
Nohoro Akai from the Oro disaster office said a full assessment of damage to buildings and infrastructure was still pending.
But an initial assessment showed that a number of landslides occurred.
"Actually we had a few landslides that covered much of the river systems, not all of them.