Korean tourists underpaid nearly $10,000

Two Korean backpackers working as cleaners at a Sydney college have been underpaid nearly $10,000 in just three months.

The pair, travelling in Australia on 417 working visas, were paid cash-in-hand at rates as low as $15 an hour between March and June this year.

The Fair Work Ombudsman says the pair were entitled to a minimum of $18 an hour, rising to $45 on public holidays.

The pair have since been reimbursed $5400 and $4085 each.

Fair Work spokeswoman Natalie James says their employer was fined $850 and issued with a formal letter of caution.

"Minimum wage rates apply to everyone in Australia - including visa-holders - and they are not negotiable," she said.

Fair Work inspectors are currently undertaking a review of working conditions for 417 visa holders as part of a three-year Harvest Trail inquiry.