Customs officers at Perth Airport have seized four kilograms of cocaine allegedly discovered hidden inside a traveller's suitcase.

Australian Border Force officers selected the 64-year old American for examination after he arrived on a flight from Bangkok, Thailand on Monday.

An X-ray of the man’s suitcase allegedly revealed two packages of white powder concealed underneath its lining; they were tested and "returned a presumptive positive indication for cocaine."

The cocaine was allegedly concealed in the suitcase\'s lining. Credit:ABF

The man appeared before court on Tuesday charged with importing a commercial quantity of a border controlled drug and remanded in custody until his next appearance later this month.