According to the USGS, the quake was registered at 11:23 GMT, with the epicenter located some 141 kilometers (over 87 miles) to the east of the town of Kimbe, at a depth of 67.8 kilometers.
There has been no information on victims or damage caused by the tremor.
Papua New Guinea is located in a seismically active zone known as the Ring of Fire and regularly suffer from powerful earthquakes. In late February, the country was hit by the 7.5-magnitude earthquake with dozens of people having been killed. Several powerful tremors were also registered earlier in March.