A trucking company involved in a fatal tanker crash on Sydney's northern beaches has been ordered to pay $525,305 for hundreds of road safety breaches.

Two people were killed and five were injured when a Cootes Transport tanker rolled on its side, burst into flames and collided with several cars on Mona Vale Road, Mona Vale, in October last year.

Fireball: the tanker crash that claimed two lives in Mona Vale last October. Credit:Tim Pascoe

NSW Roads and Maritime Services launched an investigation and charged Cootes with more than 300 offences relating to significant defects in the Victoria-based company's fleet, including faulty brakes and suspension.

Last month, Cootes pleaded guilty to 255 charges.