Suspected worm rot is believed to be responsible behind two Tauranga pontoons snapping off in last week's storm.
Strong winds and waves lashed the pontoons at Trinity Wharf, Dive Cres, forcing the piles on each to break off and a pontoon to sink.
A Tauranga City Council spokesman said two pontoons were broken with up to three piles on each damaged.
"The piles snapped off at sea level, which is part of the logistical problem there is as they might need to replace them with steel piles," the spokesman said.
The council was made aware of the damage on Wednesday and has since cordoned the area off while the damage was assessed.