An elderly woman is in a serious condition after being hit by a car in Te Kuiti.

Waikato police Senior Sergeant Juliet Burgess said the woman was crossing Hangatiki Rd (State Highway 3), about 8.30am today when she was hit.

Initially, the woman's condition appeared stable, but a St John Ambulance spokesperson said her condition had since deteriorated.

The victim is being flown to Waikato Hospital by the Westpac Waikato Air Ambulance in a serious condition.