A couple dumped soya sauce, chilli sauce and rubbish on a neighbour's car in an attempt to force him to change his parking space.

Lau Kin Kee and husband Ng Choon Meng, both 40, were caught in the act by surveillance video. Both pleaded guilty to committing mischief. She was fined $2,000, while her husband was fined $1,000 on Monday.

They told the district court that the car's headlights would shine into their flat whenever the neighbour, a drug enforcement officer, parked his Honda Jazz in that particular parking space at night. They admitted that it was not prolonged but it bothered them and they poured chilli sauce on the car on March 27.

At about 12.15am on March 31, the couple threw tissue paper soaked with dark soya sauce and a white plastic bag containing rubbish onto the car at the multi-storey car park in Punggol Central. Four days later, she poured soya sauce on the car.

Ng, a factory worker, pleaded for leniency saying that they were expecting their first child in December. His wife is unemployed.

Deputy Public Prosecutor Carene Poh said that offences were "very anti-social and unneighbourly".