Salvage teams are back on board the Rena assessing the noxious fumes emanating from the now rotting cargo on the grounded cargo ship.

Maritime New Zealand says salvors are taking advantage of improved weather conditions and have re-boarded the ship after evacuating last night.

Environmental officers are on board Rena assessing the noxious fumes emanating from rotting cargo on the grounded ship.

MNZ Salvage Unit manager Bruce Anderson says environmental officers are on board the stricken vessel and will be assessing the noxious fumes and investigating the rotting cargo.

When Rena grounded on October 5 it was holding 121 containers of perishable goods, including containers carrying burger patties that washed up on Mount Maunganui beach.

Bruce says salvage teams will also continue with the work started on Wednesday to transfer oil and lubricants to a centralised tank, which would make it easier to pump oil oils onto the Awanuia, once it is back on site.

Bruce says dive teams are taking advantage of the milder sea state and hope to continue assessing the damage to the hull of the ship.

'The first team went on board early this morning and today Svitzer expects to have a total of 22 people working on the site.

'The salvage team will continue to take advantage of the improved weather while they can.”

Weather is expected to deteriorate again on Friday.

National Oiled Wildlife Response Team coordinator Helen McConnell says nearly all of the 406 animals in care at the wildlife centre in Te Maunga have now been cleaned.

Helen says many of the oiled animals collected by field staff are dehydrated or hypothermic when they are picked up, and must be stabilised before being cleaned.

'We have to make sure they are hydrated and strong enough to withstand the cleaning process, which is quite a traumatic experience for wild animals.

'We now only have half a dozen animals that still need to go through the washing process, which is fantastic. They are all expected to be strong enough to clean over the next few days.”

'This will be a significant milestone for us as it will be the first time all birds at the centre are oil free. We can now concentrate on getting the birds back to good health.”

MNZ National On Scene Commander Alex van Wijngaarden says shoreline clean up assessment teams are on the beach at Papamoa this morning following up on reports of oil in the water yesterday.

Members of the public are encouraged to call 0800 OIL SPILL if they see oil or 0800 333 771 if they see oiled wildlife.

'It's really important that people continue to call in with these reports. Members of the public are our eyes on the ground out there and we really appreciate the intelligence they give us.”

Around 230 volunteers are expected to take part in ongoing clean-up efforts around the Bay of Plenty today.