The Rena remained in a fragile state last night as forecasts of more bad weather renewed fears the ship may break apart.
Increasing winds were predicted to peak today at speeds of 30 knots, bringing swells up to 4m high, Maritime New Zealand reported.
The bad weather is forecast to settle after Saturday.
A 30m-wide rainbow oil sheen was yesterday seen stretching up to 5km from the vessel.
Some darker patches of oil were visible around the ship.
Salvors have been modifying a crane used to lift containers from the ship and have also been installing large steel patches in the Rena's internal corridors, to improve buoyancy.
Three of the patches, weighing about 700kg each, have been installed and work on installing another three is almost completed.
Dive teams inspecting the Rena's hull have found slight changes in the buckling in the starboard side, although motion sensors attached to the hull have detected no significant change in movement.
Efforts to clear containers from the ship have halted, but a recovery team has found part of a container from the Rena at Te Kaha on the East Cape. It has been brought back to Tauranga
Meanwhile, things have changed at the animal rescue centre.
It was once just a few tents, which then grew into a bustling village, with visits by politicians and camera crews almost an everyday occurrence.
Now the oiled wildlife response centre at Mt Maunganui is almost back to the way it was in the opening days of the Rena disaster more than two months ago, with most of its feathered refugees back in their oil-free habitats.
A line of large marquees, including a post mortem tent where remains of oiled birds were kept in containers, have disappeared, as has a large shelter where penguins were carefully washed and scrubbed.
Several swimming pools are still there - as are a row of timber and mesh "penguin palaces" - but most are empty.
It has been weeks since any new cases were brought in.
Almost 50 more little blue penguins will be set free at Mt Maunganui beach this morning, marking what will likely be the last large wildlife release of the disaster.
They spent yesterday paddling about in pools to prepare for freedom, before receiving their last feed of fish.
About 60 other penguins will stay at the centre, either because of their health or because their homes are not yet clean.
Two sick and endangered dotterells are also still at the centre.
The numbers have dwindled from 360 birds at the height of the crisis, and the number of rostered wildlife workers on site has dropped from 100 to between 30 and 40.
Centre director, Dr Brett Gartrell, yesterday said it wouldn't be long before staff numbers wound down to 15 or so.
The return of the rest of the penguins in the next fortnight would mean most of the workers will be able to head home for Christmas - but he expected that wouldn't be likely.
There was still much work to be done on Motiti Island - a key habitat for penguins - and a wildlife team were due on the island for another assessment today.
At the base of Mt Maunganui, carpets are being laid over oiled areas to protect penguins arriving back home.
Things have settled down, but Dr Gartrell said days were still busy for those having to prepare twice-a-day meals for the penguins.
The Rena still looms on the horizon with what could be 100 tonnes of oil still in its ruptured belly, there was no telling for how much longer the camp would be there.
"It's all still up in the air. It's quietened down now, but if the ship breaks up, we would have everyone back, have everything back up and be at the same capacity we were in the first days," Dr Gartrell said.
"I'm pleased with the way the operation has gone. It's been a long and protracted operation but it's not over yet - and I hope we won't have any more birds through."