Archaeologist Michael Taylor remembers the World War II pillbox guard post that stood at Whanganui's North Mole during his childhood.
"My father used to fish at the Mole and my brother and I would play in the pillbox," he said.
"Things have shifted around a fair bit since the 1960s but it was definitely in that location."
Taylor said he moved away from Whanganui for a number of years and discovered the relic had disappeared beneath the tarseal near the Morgan St carpark when he returned.
Castlecliff resident Lynne Douglas has been watching the old guard post with interest since it was exposed by the tide in 2016.
The area is currently closed to traffic and high tides have washed away the tarseal to reveal a shell rock roof.
"I wondered if it was added to camouflage the pillbox," Douglas said. "You can see that it has been cemented in place."
Taylor said the shell rock would almost certainly have been placed there to disguise the structure.
"I have not climbed onto the roofs of other pillboxes in the area but I suspect the coating on that particular one was added so it would blend in with its surroundings."
Douglas has a long-held fascination with the pillboxes built as defences against the threat of invasion by Japanese forces from 1942 to 1944.
"They are an important part of our history and I was pleased that they were mentioned at the North Mole and Morgan St rejuvenation meeting last week."
Douglas said the Castlecliff pillboxes were not marked on the artist's impression plan presented by Progress Castlecliff facilitator Jamie Waugh.
"He assured me that they will be incorporated as they are part of the area's heritage."
According to the Whanganui District Council archives, 28 pillboxes were built in Whanganui between 1942 and 1944 and up to 18 of them were in Castlecliff
The pillbox at the North Mole is an arrowhead (T49) type with a central firing area and wings at either side for living quarters.