A rally driver in Serbia lost control of his car and hit a group of spectators, killing three people and injuring another, Serbian state television network RTS says.

The accident happened in the Tara mountain region in Serbia's southwest, where driver Branimir Simic of Bosnia lost control of his car and hit four spectators a few hundred metres from the finish line, media reports said.

The cause of the crash was not immediately clear.

One victim died on the way to a regional hospital, another during an operation and a third in an emergency room in Belgrade, where she had been transported with severe head wounds.

The fourth victim was out of danger, RTS said.

"All safety measures in place for such rallies were followed," rally organiser Dragan Simic told RTS. "We are investigating to establish how the spectators came to be in the spot where the accident occurred."

The race, in which some 50 teams were participating, was called off after the crash.

- AAP