Maritime New Zealand says there has been a new but small leak of oil from the stranded container ship Rena stuck on a reef in the Bay of Plenty.
It says the oil, from cracked pipes, had been trapped in wreckage in the ship's hull.
The authority says staff have made two observation flights over the ship and believe the rough swells have released about half a tonne of oil into the sea.
It says it is possible some will wash up on beaches at Papamoa and Mount Maunganui, and teams will be on standby to clean it up in the next few days.
About 350 tonnes of Rena oil has washed ashore since the ship grounded two months ago.[image:4008:full]