They say that 17-year-old Ayrton Larose was last seen in town at around 1 pm yesterday.
Anyone with any information has been asked to get in touch with the police on 612612.
Ayrton was last seen wearing a grey hoody, carrying a burgundy rucksack and may have been carrying a grey motorcycle helmet.
An earlier appeal for 26-year-old Thomas Brown has been cancelled, after he was found safe and well.