Partygoers at this weekend's Bal en Blanc will be under tight surveillance, as organizers and the Montreal police force collaborate to discourage people from taking drugs at the annual rave.

"People who want to take drugs will always find a way to come in, but we make sure that there is prevention, and we prevent them from doing so," said Bal en Blanc organizer Paul Gilbert.

This year marks the 15th edition of the rave at the Palais des Congres, known as one of the biggest dance parties in Montreal.

About 15,000 people, dressed entirely in white, are expected to attend the affair.

Organizers have spent $30,000 to have police officers in uniform at the entrance, and in plainclothes on the dance floor.

They have also hired extra security guards to search revellers for drugs.

Every year, about a dozen people are arrested at the event for drug possession and trafficking, according to Montreal police Const. Anie Lemieux.