The magnitude 6.0 earthquake is the latest in a series of powerful aftershocks that have plagued the Highlands region since the massive 7.5 struck last Monday.
The epicentre of today's quake was located 112 kilometres southwest of Porgera at a depth of 10 kilometres.
It struck just before 6am local time (9am NZT).
Due to severely disrupted transport and telecommunications links, it's still unclear how many people died in last week's 7.5 quake.
As many as 80 deaths have been reported so far, according to the PNG Red Cross.