The driver and passenger of a car in Dunedin both face charges after the passenger slapped a bicycle.

Constable Jon Dunn, of Dunedin, said a 17-year-old male passenger in a car slapped a cyclist's bike on Main South Rd, in Sunnyvale, last night.

The 16-year-old driver had swerved so the passenger could hit the bicycle.

The cyclist was put off balance and nearly fell, Const Dunn said.

A motorist driving ahead of the car saw the incident and made the teenagers stop the car, took the keys and called police.

The passenger was charged with assault and the driver with careless driving, he said.

- shawn.mcavinue@odt.co.nz