Waitematā Police are still looking for missing French man Eloi Jean Rolland.
The 18-year-old was reported missing to Police a week ago.
Detective Senior Sergeant Marcia Murray said the last confirmed sighting of Eloi was 7.26am on Saturday, March 7 at the Fruitvale Rd railway station in New Lynn.
Inquiries on Eloi's mobile phone indicate he was in the area of Piha Rd at 9.18am that day.
A Search and Rescue team began conducting a search around the Piha Rd area yesterday afternoon, Murray said.
"This search effort has been scaled up today, with the SAR team conducting land-based searches in the Piha area.
"We are urging anyone that lives in the Piha area that may have seen Eloi on Saturday 7 March to contact police.
"Likewise, we are asking anyone travelling along Piha Rd that has dash camera footage from that morning to get in touch with us."
Police are urging anyone who may have seen the teenager to get in touch.
"As time passes since the last confirmed sighting of Eloi, our concerns for his wellbeing continue to grow," Murray said.
"I would like to acknowledge those members of the public who have contacted police so far.
"We have received a number of calls and we will work through assessing the information provided."
Eloi speaks limited English and is described as 170cm tall and of thin build.
He was last seen wearing a blue and white jacket, jeans, and dark sneakers.
Anyone with information can contact Waitematā Crime Squad on (09) 839 0697 and quote file number 200310/8987.
You can also contact Crimestoppers anonymously on 0800 555 111.