The campaign, being run in conjunction with St Helens Primary Care Trust, launches later this month and is timed to coincide with the onset of the school holidays.
As well as sexual health, media relations and exhibition work will also tackle teenage pregnancy.
The campaign comes amid a national media furore over sex education, sparked by the case of three sisters in Derby who became pregnant at 12, 14 and 16.
According to latest figures, the North-West has one of the highest rates of sexually transmitted infections outside London. Rates of chlamydia in the region have increased by 262 per cent in the past ten years.
The council is stressing that while many infections have no symptoms, they can have serious health consequences if left untreated.