Salvors working to pump oil off the Rena suspended work early this morning to allow oil in the tank to rise to the top.
Less than 150 tonnes of the original 358 in the submerged number five starboard tank - the least accessible on the container ship - remains onboard.
Maritime New Zealand (MNZ) said pumping was suspended about 1am to allow the oil to rise to the top of the sea water in the tank.
"The salvage team will attempt to resume pumping later this morning," MNZ said.
The Rena stranded on Astrolabe Reef off the Tauranga Coast on October 5, spilling oil into the sea and sparking a massive clean-up effort.
MNZ national on-scene commander Rob Service yesterday said he had hoped some beach access restrictions would be lifted this weekend but that was now unlikely to happen until next week.
Restrictions remain in place from Tay St in Mt Maunganui to Maketu.
"We have a process to follow before we can lift the access restrictions, including ongoing surveys and consultation with key parties," Mr Service said.
"We know people want to get onto some of those beaches, but we can't rush in - we must ensure we have worked carefully through that process."