FREDERICTON - A new trial has been ordered for a New Brunswick man convicted of assault for spanking his six-year-old son in Fredericton in 2009.

The New Brunswick Court of Appeal has ordered the new trial, ruling the trial judge applied a subjective standard concerning the duration of the spanking.

Court documents say the man, his wife, the six-year-old and the couple's two other children were driving to a museum in Fredericton in August, 2009.

The boy was bickering with his brother, yelling at passing cars and kicking the back of his mother's seat as she was driving.

The father told the court that after efforts to reason with the boy failed, they stopped at a school parking lot and he spanked the boy, striking his clothed buttocks two or three times.

A witness says she saw the man hit the child at least 10 times.

The Appeal Court decision says the trial judge failed to properly explain the reasons for her ruling.