Another four people have been charged in connection with a smashed drug ring in Brisbane's south.

Police investigating a syndicate where they seized $1.8 million in cash on Tuesday swooped on another four addresses across the city's south on Wednesday.

More than $1 million in cash, suspected to be proceeds of crime, was seized in the raids. Credit:Queensland Police Service

A 26-year-old man, two 22-year-olds and a 23-year-old woman were charged with a variety of drug offences after raids on properties in Doolandella, Coopers Plains, Forest Lake and Augustine Heights.

Police seized drugs at all four addresses and a further $36,350 in cash at the Forest Lake residence.