Police intercepted a van in Pinjarra on June 9 after residents reported being approached by art sellers going door to door selling artworks for $170 or more.
The trio were questioned and more than 100 paintings confiscated.
Acting Commissioner for Consumer Protection David Hillyard said sellers may still be operating in Perth�s southern suburbs or in the South-West.
By law, a 10-day cooling off period applies to unsolicited sales in which payment for items over the value of $100 cannot be taken for 10 business days.
�If consumers ask them to leave, they must comply immediately and cannot make contact for at least 30 days,� Mr Hillyard said.
Traders are banned from door-knocking on Sundays and public holidays and sales are restricted to between 9am and 8pm weekdays and 9am to 6pm Saturdays, unless they have made a prior appointment.
Consumers may consider displaying a sticker which reads: �Do not knock – Unsolicited door-to-door selling not welcome here� and sellers must legally comply. The stickers are available from Consumer Protection.
People approached by these art sellers should contact Consumer Protection at firstname.lastname@example.org or call 1300 30 40 54. For more information, visit the Consumer Protection website www.commerce.wa.gov.au/doortodoor.