Moving protective rocks from one part of Kai Iwi Beach to another has killed a mussel colony and exposed a fragile headland to erosion, George Matthews, the spokesman for the local Tamareheroto hapū, has said.
Matthews said moving the shellrock was a short-sighted, cheap fix and was "robbing Peter to pay Paul".
And the southern headland that the rocks were placed to protect will be gone in five to 10 years, leaving the beach exposed to south and southeast wave action, a Whanganui District Council report said.
Pieces of limestone rock rip rap were placed at the bottom of the headland 30 to 40 years ago, a council spokeswoman said. Storms in 2017-18 dislodged them, and the beach lost a lot of sand as a result.
Meanwhile the coast to seaward of the Kai Iwi toilet block was also eroding. About 200 tonnes of the "ineffective" rock from the headland was moved there, with another 100 tonnes from elsewhere added. Concrete and steel from the foot of the headland was also removed, because it was unsafe.