Kia Motor's Rio is being investigated by the U.S. federal safety authority after complaints about engine failures, according to a report in the Korea Times.

The US National Highway Traffic Safety Association (NHTSA) is investigating 61,448 Rios produced since 2001.

The inspection was sparked by complaints from about 5 per cent of owners that the cars' engine broke down or caught fire.

The NHTSA is also scrutinizing three other models including Honda Accords made in 1998 and 1999, CR-Vs manufactured in 2002 and General Motors' Saturn L-series produced in 2001 and 2002.