The sinking of Rena's stern could be good for Tauranga's tourism industry if it remains at sea, says the city's mayor.
About 75 per cent of the stern section of the wrecked vessel on Astrolabe Reef slipped under the water on Tuesday morning, spilling oil, debris and containers.
The ship split in two following a severe storm at the weekend.
Tauranga Mayor Stuart Crosby told NZ Newswire he hoped the wreckage would become a diving attraction.
"A lot of it will depend on where it settles," he said.
"It would be best if it was completely off the reef."
Most of Rena's stern has slipped off the reef, with just the tip still visible above the rough seas.
The bow section remains in place on the reef, where the container ship has been wedged since its grounding in October.