That is the advice of Senior Sergeant Anthony Bond, of Dunedin, after a group of young people were spotted doing burnouts on the Sunnyvale sports ground.
Police were called to the ground in Green Island about 9pm on Monday.
Snr Sgt Bond said a 17-year-old youth was seen doing burnouts on the grass near the entrance and his car got stuck.
He was joined by two of his 16-year-old friends, who were driving mopeds.
They too began doing burnouts and covered the car in mud.
A local reported the incident to police.
"Sports fields are for playing sports on, not for driving on," Snr Sgt Bond said yesterday.
Officers took the youths back to their parents.
The matter has been referred to Youth Aid.