This follows the news that two employers - a Brisbane restaurant and Perth baker - have been fined for underpaying staff.

The owner of Brisbane-based Picasso Pizza and Pasta restaurant is facing court after the Fair Work Ombudsman found two employees had been underpaid $15,322 between September 2006 and January 2008.

In Perth, Efes Bakery was yesterday fined $19,500 for underpaying a delivery driver $16,204 between 2006 and 2008.

Inspectors from the Fair Work Ombudsman's Bendigo office will now write to Murray River employers asking them to evidence of their compliance with workplace relations laws.

The maximum penalty for a breach of workplace law is $33,000.

Fair Work Ombudsman executive director Michael Campbell said the audits are in response to a significant number of complaints from accommodation industry workers in northern Victoria over the past year.

"In cases where records are not provided, are not up to scratch or indicate workers are being underpaid, we will visit the employers and may launch a wider investigation.

"Where we find records are not adequate or identify other non-compliance issues, we provide information and assistance to employers and request they voluntarily rectify any problems.

"In cases where they don't, or where we suspect deliberate underpayments or other serious breaches have occurred, we may launch a full audit which could lead to court proceedings," said Campbell.