More containers are being pushed from a hold in the bow section of the Rena wreck as heavy swells batter the wreck at Astrolabe Reef.

Maritime New Zealand reports an estimated 10 containers have been lost overboard as swells of up to 7metres hit the reef, which are forecast to persist through the night.

Large swells hit the Rena wreck at Astrolabe Reef. Photo: LOC

MNZ Tauranga Response and Recovery manager David Billington says an observation flight this afternoon confirms swells have forced a hatch cover off the number 3 hold in the bow section, and an estimated 10 containers had been released from the same hold.

One of these containers was seen floating near the wreck. It is possible the others have sunk to the seabed.

David says no salvage operations can take place during the rough weather, but the salvage and container recovery teams were monitoring the situation and had contingency plans in place to respond as soon as weather conditions allowed.

He advised any boaties out on the water in the Bay of Plenty to take extra care and to observe the two nautical mile exclusion zone around the wreck site.

'There is debris in the water and this could cause damage if it comes into contact with your boat.

'Keep a really good lookout, and travel at a safe speed,” he said.

Anyone who sees containers or debris is encouraged to report it to the Braemar Howells recovery team on 0800 333 771.

National On Scene Commander Rob Service says rough seas have caused further damage to the wreck and a small amount of oil has been observed in the immediate vicinity.

'There is only a small amount of oil remaining on the wreck but, as we saw last week, even a small release can result in patches of oil reaching the shoreline,” says Rob.

'Our teams remain ready to respond if this does happen.”

Members of the public are encouraged to ring the oil hotline on 0800 OIL SPILL (0800 645 774) to report any sightings of oil.