Five children have been approached by men offering rides in the Cessnock area in the past week.
Since last Thursday, when two siblings and a girl were approached, police have responded to a further two cases with no apparent link.
A 13-year-old boy was approached while waiting for a bus at Nulkaba on Thursday at 8am.
A green Commodore stopped near the boy, at the intersection of Wine Country Drive and Kerlew Street, where the driver asked for directions to Cessnock jail.
The boy declined an invitation to get into the vehicle.
The car was last seen driving along Wine Country Drive towards Lovedale.
The driver was described as being aged between 40 and 50 years with a sunburnt complexion and wearing a dark, hooded jumper.
Only 24 hours earlier, at 8am Wednesday, a 13-year-old girl was walking along View Street at Cessnock when a white van pulled up beside her.
A passenger in the van, who had his face covered, had a brief conversation with the girl who ran from the area.
The van followed her for a short distance and was last seen travelling along View Street.
The passenger is described as having a big chest. He was last seen wearing black gloves and a black jacket.
The girl was unable to describe the driver.
Last Thursday, about 8.20am, a 19-year-old man and his 12-year-old brother were walking along Mount View Road, Cessnock when a man approached them.
Police have been told the man, who was driving a silver or white coloured four-wheel drive, offered them a lift to school.
Ten minutes later a 13-year-old girl was walking along Mount View Road near Scott Street when the man also approached her.
Police from the Central Hunter Local Area Command said the man is of Caucasian appearance, 50 to 60 years old, with a medium build and balding brown/grey hair. He has scarring on his cheek/chin and was wearing dark sunglasses and a blue, white and grey chequered flannelette shirt.