Police are appealing for help to find three boys and their mother who are missing from south-western Sydney.

Mother Elizabeth Harpley was last seen at Koshigaya Park at Campbelltown on Sunday afternoon.

A short time later she and her three sons ten-year-old Mathew, nine-year-old Christopher, and five-year-old Mitchell were reported missing also

They’re believed to be with a man who is known to them and maybe travelling in a red Jeep with Queensland registration plates.

Campbelltown, Wollongong, and Pullenvale in Queensland have been flagged by police as areas they’re known to frequent.

There are concerns for the three boys, who require medication.

Anyone who sees them is urged to contact Triple Zero.

Image: NSW Police