Residents living near Rangituhi/Colonial Knob have been urged to check their gardens, shed and work sites for an elderly man with possible dementia, missing since Sunday.
Graham Russell Smith, 77, went missing while going for a walk at 6.30pm on Sunday on Doctor Track on the Colonial Knob walkway.
He has been described as 165cm tall, of slight build and wearing a blue puffer jacket and brown corduroy pants.
Smith was potentially suffering from dementia and had difficulty hearing, a police spokesperson said.
Workers in the in the industrial and commercial area near Rangituhi/Colonial Knob, southwest of Porirua, should check their gardens, out buildings, sheds, and work sites for Smith, the spokesperson said.
Residents in the areas of Elsdon, Kenepuru Landing, or on the western hills of Tawa that back onto the scenic reserve, should also check their gardens, the spokesperson said.
"A significant search effort is under way to locate him, and we are concerned for his welfare."
The area where Smith went missing had multiple walkways and mountain bike trails, the spokesperson said and was an extremely popular area for walkers, day trampers and mountain bikers.
Police believed it was likely members of the public would have seen Smith and anyone who saw or interacted with him should call 111 and reference the file number 241111/3559.