Police are appealing for witnesses after a man was stabbed at a park in suburban Sydney.

The 29-year-old man is in a serious condition after being stabbed several times in the neck on Saturday night after he was involved in a fight with a group in The Ponds in north-western Sydney.

The group, believed to comprise eight males and a female, are said to have fled the scene in different vehicles.

Police are appealing for information.

AAP