Canada Border Services agents have made a massive cocaine seizure at a border crossing south of Vancouver.

The border services agency says it discovered 144 bricks of the drug hidden inside a commercial vehicle last weekend, one of the largest seizures ever made at a Western Canada land crossing.

The stash of one-kilo bricks was spotted when agents were examining a tractor-trailer rig and turned up some alterations to the trailer's refrigeration unit.

Officers arrested the drivers after tests revealed the hidden cargo was cocaine.

About 1.35 tonnes of cocaine have been seized at Pacific Region crossings since 2007.