The Perth Mint, owned by the West Australian government, buys up to $200 million of "conflict gold" annually from a convicted killer in Papua New Guinea, a breach of its global accreditation and internal policies.

An investigation by The Australian Financial Review can reveal the historic mint has repeatedly ignored staff concerns over purchases from small-scale gold miners in PNG, a practice heavily criticised for using child labour, degrading the environment through the use of mercury, and promoting conflict.