"The mine is conducting a thorough geotechnical and structural evaluation before recommencing operations," Harmony said.
"Preliminary investigations have identified no major damage."
The major PNG cities of Lae and Port Moresby were both shaken by the event which occurred in the mid afternoon, but there have been no reports of significant damage.
PNG is still gripped by a political crisis with both Sir Michael Somare and Peter O'Neill claiming to be the prime minister after Monday's Supreme Court ruling that O'Neill unlawfully took the top job in early August while Somare was on extended medical leave.
ABC correspondent Liam Fox tweeted that a member of parliament was talking about parliament house being cursed at the same time the earth tremors reached it yesterday.
"Bizarre moment," he said.