A Singapore beer company has been exposed for underpaying staff during the construction of its first overseas brewery in Melbourne, with its owner complaining Australia's labour market is "too expensive".

RedDot Brewhouse, which runs a commercial brewery and beer garden in the Melbourne suburb of Truganina, was investigated by the workplace watchdog for suspected exploitation.

The company that's bringing the RedDot Brewhouse concept from Singapore to suburban Melbourne has been exposed for underpaying its staff.

The craft brewer expanded into Australia to build a production plant and beer garden last year after receiving support from the Victorian government.

Inspectors from the Fair Work Ombudsman have found the company underpaid a Filipino welder more than $20,000 in three months after he was recruited for the construction of the new brewery.