The quake hit at 06:41 am in a remote area almost 250 kilometres west of the provincial capital Jayapura at a depth of 52 kilometres, the US Geological Survey said.
In its initial estimate, the USGS said there was "a low likelihood of casualties and damage".
It noted however that "the population in this region resides in structures that are vulnerable to earthquake shaking".
The Hawaii-based Pacific Tsunami Warning Center said there was no threat of a tsunami generated by the quake, which occurred inland underneath the Irian Jaya jungle.
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It cited specialist professor Max Wyss, who predicted between zero and 10 people may have been killed and up to 100 injured. A similar quake in April 2013 killed three people, the site added.
Geoscience Australia on its website estimated the quake could be felt up to 1,523 kilometres from its epicentre and could have caused damage up to 122 kilometres away.
The region lies on the 4,000-kilometre-long Pacific Australia plate, which forms part of the "Ring of Fire", a hotspot for seismic activity due to friction between tectonic plates.