Containers and debris could spill into the sea as waves up to 8m high batter the wreck of the Rena this week, authorities say.

Forecasters said a series of tropical storm systems causing flooding and slips in Fiji are set to hammer the Bay of Plenty tomorrow and Wednesday. said the wreck of the Rena on Astrolabe Reef could be in the firing line for waves averaging four metres high.

Oceanographer Brett Beamsley said maximum individual waves could exceed seven metres high.


Gale force winds were predicted in the area, though there was still some uncertainty in weather models, he said.

Maritime New Zealand said it expected waves of up to eight metres to batter the wreck.

Salvage barge the Smit Borneo had left the wreck due to poor conditions and was likely to remain in port until Sunday, it said.

"The wreck remains in a fragile state and will continue to deteriorate the longer it remains exposed to the elements. The forecast bad weather may result in further damage or movement of the wreck, along with the potential loss of more containers or container debris."

There are still 685 containers on board the Rena, which crashed into the Astrolabe Reef off Tauranga last year.