They were in a Black Ford Focus that was stopped in Corporation Road by police, who believed they were acting suspiciously.
The car was searched and a black bag containing cannabis was recovered, along with cash and a number of phones.
The driver was wiped for drugs, where he tested positive for cannabis.
Both him and the passenger were arrested on suspicion of drugs offences and have since been released under investigation.
The action was part of a police campaign targeting gun and knife crime across Merseyside.