Scandal-plagued Perth Mint allowed clients of a tax haven bank, which is being investigated for its links with global organised crime syndicates, to purchase more than $100 million of gold without conducting the identity checks required to prevent money laundering.

Insiders at the WA-government owned refiner have told The Australian Financial Review the Mint relied on the vetting processes of Puerto Rico-based Euro Pacific Bank, an institution revealed on Monday to be under investigation in five countries.