A sister and brother have been approached by a stranger who tried to entice them into his car on NSW's midnorth coast.

The 12-year-old girl and five-year-old boy were playing in a vacant lot near their home in James Grimwade Place, East Kempsey, about 1.30pm (AEDT) on Sunday, police say.

A red Nissan four-wheel-drive with a silver bull bar stopped on the roadway, and a man with curly brown hair and a clean-shaven face called the children over.

They approached and the driver, aged in his mid to late 40s, asked them to get into the car.

The pair immediately ran home and told their mother what had happened.

Police are appealing or information about a man who may be able to assist with their inquiries.