The operations began at 7 a.m. Tuesday and involve about 50 investigators with the Unité Permanente Anticorruption, or UPAC.
The raids targetted three construction companies, G. Giuliani Inc. in Laval, Asphalte Desjardins Inc. in Terrebonne, and Construction DJL in Boucherville.
A spokesperson for the anti-corruption unit said Tuesday's raids are tied to raids conducted over the last few weeks.
Last week the anti-corruption unit executed search warrants on at least six construction companies in Laval. The week before that, it hit the homes and offices linked to the city's mayor.