More than 1400 vehicles with tow bars inspected by Auckland-based certifier Patrick Chu have had their safety certifications removed.

Photo: Supplied.

The Transport Agency said Mr Chu was using the wrong assessment standard when he checked the vehicles, which means the tow-bars were incorrectly deemed safe.

The vehicles with them included more than 1400 trucks, motorhomes and vans.

Agency managing partner Steve Haszard said there was a risk that trailers could detach from the vehicles.

Mr Haszard has urged anyone who had their tow-bar checked by Patrick Chu to have it reassessed by another certifier.