Traffic chaos after van with explosives rolls on Sydney freeway

The bomb squad today spent hours scouring the side of a busy Sydney freeway after a vehicle carrying 'explosives' rolled.

Police were called to the M7 at Cecil Hills in the city’s southwest after the vehicle rolled after 9am.

It is understood a minibus carrying cheerleaders from Canberra to Sydney collided with the rear of a four-wheel-drive, which had been carrying explosive rail detonators. 

In the collision, 48 of the detonators were strewn across the freeway and into long grass. While 45 of them were located, multiple police teams were called in to find the missing three.

Rail detonators are coin-sized devices used as a warning signal for train drivers. While they can't be exploded on their own, police claimed they could be dangerous if in the wrong hands.

The crash sparked significant traffic delays in the area.

The cause of the crash is not known and no one was injured.