Gang members using fake identities have been renting homes in Perth and turning them into hydroponic cannabis farms, prompting a warning to landlords.
Consumer Protection said 21 homes in the past seven months had been rented by members of southeast Asian gangs based in the eastern states, with the growing systems causing $70,000 worth of damage at one property.
Acting commissioner David Hillyard said specific suburbs weren't targeted and applicants did not use real estate agents, preferring private rental adverts through sites such as Gumtree, and often made offers to landlords.
"In some cases they negotiated with the landlord to pay more to have their electricity bill covered, that has really backfired on the owner," he told ABC radio.
"He now faces an $85,000 power bill as a result of them using the electricity."
WA Police have seized $6 million worth of cannabis from the properties and estimate the value of stolen power to be $1 million.
Mr Hillyard advised private landlords to conduct proper background checks on applicants, and to schedule their first property inspection about one month after a new tenant moved in.
He said some of the applicants posed as families with young children, and targeted landlords from similar cultures.