A toddler is a critical condition after a near drowning in southern Lake Macquarie.

Police and paramedics were called to the house in Dale Avenue at Chain Valley Bay just after 4:30pm (AEDT) yesterday afternoon.

The two-year-old had been pulled unconscious from a backyard swimming pool.

He was treated at the scene and flown to Newcastle’s John Hunter Hospital.

Police are still investigating the circumstances surrounding the incident.