UPDATED 2.37pm Land and sea searches are continuing for a 21-year-old woman missing in Piha.

Kim Bambus was last seen in Ponsonby on Friday when she told her flatmates she was going running on Piha's Ahu Ahu bush track.

Search party numbers have halved since yesterday - with around 22 people scouring the bush around Log Race Road, Ahu Ahu track and Mercer Bay.

Surf life savers and helicopters are combing the coastline for any sign of her.

Police are working through new information after receiving several calls from the public last night.

NZ Herald Focus reporter Tristram Clayton said Kim's friends and family are waiting at the search party's base for any word.

He said Kim's sister Storm Bambus believes Kim visited the track as little as 10 days ago and it was a spot she visited occasionally.

Police still want to hear from anyone who used the bush track on Friday and ask people to call police on 0800 528 337.