A recent data breach at Perth Mint saw hackers take the personal details of about 3200 customers, far more than initially suspected, but investors have been assured their investment remains safe and secure.

The mint said earlier this month the breach occurred on the system of a third-party technology provider and only involved 13 customers of the Depository Online precious metals trading platform.

On Monday, the mint said it had emerged the number of affected customers was much higher than first thought, but their investments were safe and there was no evidence to suggest internal systems had been compromised.