According to a statement on its website, Banister Law, together with Gilbert + Tobin, filed the suit in the Federal Court alleging some vehicles were fitted with defective diesel particulate filters meant to trap and burn soot from the engine.

"The affected vehicles ... require time consuming and costly repairs, including repeated vehicle servicing and repeated replacement of the (diesel filters) in its entirety," Bannister Law said in the statement.

Representatives from Toyota's Australian unit did not immediately return emails seeking comment.

The lawsuit, filed on behalf of customers who purchased the cars between Oct. 1, 2015 and July 26 2019, seeks compensation for the alleged loss and damage suffered by the group, the statement said, without giving any details on the amount.

The lawsuit also alleges Toyota made misleading statements because the vehicles "could not, and did not, deliver the advertised combination of durability, reliability, quality, comfort and convenience, and the (diesel filter) in the affected vehicles was not durable, reliable and of good quality".

Toyota's Hilux is Australia's top selling car, according to comparison website Canstar.

In June, Toyota Motor Corporation Australia posted a 50% increase in after-tax profit to A$206 million ($141.21 million) for the year ended March 31, 2019, according to its website. The company sold 223,096 vehicles in the country over period.

Toyota, Japan's biggest automaker, sold 10.6 million vehicles globally in the same period.