A chain of suburban hairdressing salons has been caught under-paying dozens of employees almost $300,000 following an investigation by the Fair Work Ombudsman.

Siajj Pty Limited, which operates seven salons, branded as 'What's Up Hair' or 'Best Cuts and Colour', failed to pay correct minimum wages, casual loading and penalty rates.

The company's director and owner Zena Suleiman was also found to have routinely breached record-keeping laws, which hampered the ombudsman's investigation.

At one salon in Wantirna South, almost 50 staff were underpaid $88,000 between January 2015 and July 2016, with one woman denied $9,680 in entitlements over the 18-month period.