Current trajectory models showed fresh oil could potentially reach Maketu tomorrow evening, Maritime New Zealand (MNZ) said.
Booms - floating devices used to contain oil - were being placed at Maketu and Little Waihi Beach and the National Response Team was ready to clean up any of the oil, national on scene commander Alex van Wijngaarden said.
"We are regularly monitoring the oil on the water with aerial observation flights. The most recent one confirmed a stretch of sheen with some dark patches in it spreading about 500m from Rena. A lighter sheen, with no dark oil spots, stretches around 10km from the wreck."
Teams were currently cleaning oil at Matakana Island and Mount Maunganui, while rapid response teams remained on standby.
No oiled birds were found overnight.
Volunteers in Waihi are being trained to take part in beach clean-ups after they asked to be involved at a community meeting yesterday.
A helicopter was patrolling the coast checking for floating containers between Waihi and Matakana, MNZ said.
Five containers and their contents have been removed from Waihi Beach and recovery teams were working to remove 10 more.
Plans were underway to remove 11 containers from Matakana Island.
It was confirmed yesterday that around 400 containers were still in in the stern section of the ship when it began to sink.
Earlier it was estimated around 150 containers fell overboard when the ship split in two.
Claudine Sharp of recovery specialist Braemar Howells said 45 containers had been identified and of these, 25 had washed up on the beach or come ashore.
Meanwhile, the Green Party has reiterated its call for an independent inquiry into the Government's response to the Rena disaster, saying the ship's sinking might have been inevitable but the disaster was not.
"With the sinking of the stern section of the Rena the Government has stated its focus is to minimise environmental damage, yet better planning and precaution could have been avoided it all together," Green Party oceans spokesman Gareth Hughes said.
"The only way we can fix the causes of the accident and improve our response is by taking a critical, independent look, which the Government has not committed to.
"It is unlikely Maritime New Zealand, salvors or politicians will be critical of their response. An independent inquiry is needed to ensure the lessons are learnt and changes put in place."
