Consumers have been warned not to deal with an Alexandria automotive business which is being investigated for failing to deliver at least $600,000 to customers in consignment deals.

NSW Fair Trading issued a public warning about Gasoline Machine Pty Ltd and Gasoline Australia (NSW) Pty Ltd, both of which are trading as Gasoline Motor Co and have had their license to trade suspended pending a response by the licensees.

The public warning also advises consumer not to deal with the sole director of Gasoline Machine, Matthew Hale, or the sole director of Gasoline Australia, Jason Leppa.

The company, which describes itself as a "contemporary institution of avant-garde recreational and mechanical entertainment", lists Ducati and Harley Davidson motorcycles in its high-end stock.