A fourth woman has come forward with a sexual assault complaint after a man and woman were charged with a series of rapes on women over a six month period near Hamilton.
Police said there might be more victims yet to contact them.
The pair were facing drugs charges as well as the sex assault allegations.
The two, a 37-year-old man and a 32-year-old woman were due to appear in the Hamilton District Court today.
Detective Senior Sergeant Andy BuBear said today's appearance of the pair followed an earlier hearing on Saturday after they were arrested at a rural property between Hamilton and Cambridge late on Friday night.
"They were both charged on three counts of rape and one of unlawful sexual connection while the man faces an additional charge of carrying out an indecent act in a public place," he said.
"We can now confirm the number of victims from the pair's activities over the past six months has risen to four women," he said.
The drugs charges were for possession of cannabis and cultivation of cannabis.
Mr BuBear said police would not release any further details.
The other charges related to sex attacks in Hamilton since July and involved three separate attacks where police alleged drunken young women were lured into the back of a vehicle, before being raped.
The man was remanded in custody on Saturday and the woman was released on bail.
Mr BuBear said they were keen to hear from others "who may have fallen victim to the pair's activities".
He urged those people to contact Hamilton police.
