Speaking to Newstalk ZB's Larry Williams this afternoon Auckland Councillor Mike Lee said other wartime wrecks sunk near the Solomon Islands are already leaking. The RMS Niagara was sunk before those ships.
"We are told that with corrosion and biological bacterial activity that the bulkheads will erode away and gradually collapse."
The wreck is lying on its side and will gradually crush itself, he said.
New Zealand's oil spill contingency plans cover a six-tonne spill, Lee said. A 2000-tonne spill would be a disaster.
"I don't want to overcook it but at same time we don't want to underestimate the real risk."
He said there was concern Maritime NZ was not taking the risk seriously.
Lee said the first step was to get the wreck checked; if collapse was imminent, the oil could be removed and sea water pumped in to stop it from imploding.