An illegal casino has been discovered in a Wyndham factory.
Police raided the Truganina property overnight, arresting 21 people and seizing cash, gaming tables, equipment and drugs.
It is alleged the casino has been operating weekly without a licence, with up to 50 people attending each night.
Police say there has been a minimum $8,000 buy-in to attend.
A 35-year-old local man, alleged to be the operator, is expected to be charged on summons with offences including conducting unauthorised gambling and advertising unauthorised gambling.
The other patrons arrested during the night are expected to also be charged.
Detectives from the Westgate Divisional Response Unit were supported by the VIPER taskforce, Liquor Unit, the Dog Squad and Done unit during the raid.