Police in Perth believe they have smashed a syndicate which tried to import drugs worth $13 million into the country.

Federal Police and Customs officers say they found 35 kilograms of methylamphetamine concealed in a container of ceramic tiles from China.

The drugs were found at the port of Fremantle earlier this month.

Police later raided four properties across Perth and arrested three men and a woman aged between 21 and 49.

They also seized more than $38,000 in cash and another two kilograms of drugs.

All four are due to appear in a Perth court today.