Busselton detectives have charged a 42-year-old Yalyalup woman with a string of drug offences.
Police were conducting a traffic stop on Bussell Highway in Capel on the morning of July 15 when they searched a Holden Commodore sedan.
"It is alleged a quantity of methylamphetamine was located that police believe was to be sold in the South West," police said.
The woman has been charged with 18 counts of offering or supplying a prohibited drug and possessing a prohibited drug with intent to sell or supply.
The car was seized by officers.
The woman has been remanded in custody and is due to appear in Bunbury Magistrate’s Court on August 4.