Salvors on board the grounded cargo ship Rena have pumped 21 tonnes of oil onto the barge vessel Awanuia overnight.

Pumping of oil got underway at 6.30pm yesterday with salvors working through the night and into this morning to remove some of the estimated 1300 tonnes of oil still on board.

Salvors have pumped 21 tonnes of oil from Rena overnight.

It has now been 13 days since the container ship became grounded on Astrolabe Reef on Wednesday, October 5 leaking more than 350 tonnes of oil into the ocean.

Maritime New Zealand Salvage Unit head Bruce Anderson says pumping continued successfully throughout the night.

'Considering the oil is the consistency of marmite and has to be pushed through 150 metres of hose, this represents an excellent effort.

'Night time operations have given us additional lead time, particularly given the expected change in weather conditions forecast for later today.

With rough seas and up to 30 knot winds expected this evening and early Tuesday, Maritime NZ is warning further oil could leak from Rena.

'Every bit of oil that is removed from the damaged vessel reduces the risk of further oil spilling into the environment.”

Maritime NZ National On Scene Commander Nick Quinn says clean up crews will continue to look for oil along the coastline today.

'We will be focusing on scientific monitoring and surveillance of further patches of oil that come ashore, and will continue to send teams out to pick up oil as needed.

Nick says people are urged not to collect or eat any shellfish from local beaches, as public health warnings remain in force. This advice remains in place even for beaches that were contaminated and which have now been cleaned and reopened.

Most beaches also remain closed. Limited access is available at the main beach at Mount Maunganui down to Leisure Island. There is no swimming at all beaches.

'We will be continuing to assess the state of local beaches, and if it is safe do so, with no threat to public health, we may look to reopen some beaches over the coming days.

'In the meantime, we ask people to please keep off any closed beaches and to continue to report any sign of fresh oil or affected wildlife to us.”

Around 460 volunteers assisted with beach clean ups on Sunday at Mount Maunganui, Papamoa, and Maketu, while a further 260 volunteers from Opotiki to East Cape have been trained and are ready to launch into action. A further 30 volunteers were also trained in Bowentown yesterday.

'The response from the people of the Bay of Plenty has been nothing short of amazing,” As of this morning, almost 5500 volunteer registrations have been received, which is fantastic,” says Nick.

There will be two clean up teams working in Papamoa today, starting at the Papamoa Surf Club, and one working along Mount Maunganui starting from Clyde Street beach access at 1.30pm.

Volunteer coordinators at the incident command centre are rostering volunteers so their assistance can be used effectively.

As of last night, 181 live birds were being treated at the Oiled Wildlife Recovery Centre in Te Maunga and three fur seals are also in care. Approximately 1250 dead birds have been found.