Assay results of four samples at the Queensland-based explorer's New Britain project indicated copper contents ranging from 183 parts per million to 503ppm.
Geological consultant Stan Yeaman described the results as a sign of South American-style iron ore copper gold (IOCG) mineralisation.
"These results are from rock-chip character samples, which are not representative linear channel samples, but were taken to characterise the silicate alteration with the chalcopyrite mineralisation over a significant area," he said.
"There are multiple veins of this style of mineralisation within the approximately 400m width examined, but these samples do not represent average grade over that width.
"I think it would be legitimate to say that this style of mineralisation is comparable to the IOCG mineralisation mined in Chili and Peru for iron ore and copper."
Makmak is accessible via 4WD vehicle along logging tracks from Kimbe, the provincial capital of West New Britain, on the north coast of the island.