The U.S. Geological Survey said the quake measured magnitude 7.5 and was located 45 kilometers (28 miles) northeast of Kokopo, a remote town with a population of about 26,000. It was centered at a relatively shallow depth of 10 kilometers (6 miles), it said.
MORE: How earthquakes are measured
Shallow earthquakes tend to cause more damage on the Earth's surface, but the USGS estimated that damage and injuries would be low because of the area's sparse population.
The U.S. Pacific Tsunami Warning Center said tsunami waves of up to 1 meter (3.3 feet) were possible along coastal areas up to 1,000 kilometers (620 miles) from the epicenter, including Papua New Guinea and the nearly Solomon Islands. It later said the tsunami threat had largely passed and no waves had been observed, but that there were no sea level gauges in the area for measurement.
It said there was no tsunami threat to Hawaii or Guam.
MORE: What is an earthquake? This is what happens when the ground starts to shake
Papua New Guinea is located on the eastern half of the island of New Guinea, to the east of Indonesia.
It sits on the Pacific's "Ring of Fire," the arc of seismic faults around the Pacific Ocean where much of the world's earthquakes and volcanic activity occurs.
A magnitude 7.5 earthquake in February 2018 in the nation's central region killed at least 125 people and forced another 35,000 from their homes. That quake hit areas that are remote and undeveloped, and assessments about the scale of the damage and injuries were slow to filter out.