More oil from the stricken ship Rena has washed up on Mt Maunganui beach.
Maritime New Zealand (MNZ) says teams have found fresh, light oiling around Mt Maunganui and Leisure Island.
"Our focus for the next couple of days will be to get clean-up crews down there cleaning that oil," National On-Scene Commander Nick Quinn said.
"We are expecting around 200 volunteers doing clean-ups at the Mt Maunganui main beach and Papamoa tomorrow."
Subsurface oil at Papamoa and Maketu was also starting to resurface around the high water mark near dunes, Quinn said.
A landing barge is helping with the removal of oil and containers from the beaches.
Maritime New Zealand is still monitoring the direction of the between 5 and 10 tonnes of oil which spilled over the weekend.
Quinn said this afternoon it was still heading northwards towards Mayor Island and the Coromandel.
The oil would be weathered and likely to wash up on the shoreline in the next few days as tar patties or tar balls.
"We have a team going to Tuhua (Mayor Island) today to assess the use of booms to protect key areas. We have also sent teams to assess the impact any oil reaching the shore could have on wildlife," Quinn said.
Mayor Island is a wildlife refuge, home to many native birds, and has a five-square-kilometre marine reserve off its northern coast.
Half of oil removed
Meanwhile, an estimated 737 tonnes of oil have been pumped from the port tank, with just 35 tonnes left to pump.
Around 350 tonnes have leaked into the sea since it grounded on the Astrolabe Reef three weeks ago.
Another 358 tonnes of oil remains on the starboard tank and 220 tonnes are in the two settling tanks in the engine room.
Maritime New Zealand Salvage Unit Manager Bruce Anderson said the most challenging phase of the operation is yet to come.
"The salvors now have the pumping system working well and they are getting good transfer rates, which is excellent," he said this morning.
"However, the second half of the oil is in around four tanks, rather than one - and one of them is submerged underwater."
Anderson said the salvors are working on a new system to pump fuel from the engine room directly into a tug boat, rather than transferring it into another part of the ship.
"Transferring the oil direct to (tug boat) Go Canopus will hopefully speed up the process," Anderson said.