A man in Cairns allegedly kidnapped and sexually assaulted four vulnerable women over a period of almost two years, and police believe he may have approached other women.

Dennis Malcolm Johnson, 36, of Manunda, faced Cairns Magistrates Court on Thursday charged with four counts of kidnapping and three counts of sexual assault.

“Police will be alleging that he’s deliberately driven around the Cairns CBD, sometimes for hours on end,” Detective Sergeant Bradley McLeish said at a press conference today.

“And we’ll be alleging that he was deliberately driving around with the intent of finding vulnerable female victims,” he said.

Mr Johnson had already been charged with one count of sexual assault in September, after a 23-year-old woman allegedly fled his parked car and flagged down a passing motorist on the Captain Cook Highway, north of Cairns.

Further complainants, aged 19, 23 and 33, were identified after that arrest, Sergeant McLeish said.

“[They are] all unknown to each other [and] unknown to him as well,” he said.

The sexual assaults are alleged to have taken place at the man’s home and at an “unknown location”.

Detectives are appealing for any women who have been approached by a man in a late-model SUV in Cairns to come forward, even if they had little memory of entering the vehicle or being taken anywhere.

Mr Johnson has been remanded in custody to next face Cairns Magistrates Court on November 24.