Shipments of oil from the north to the industrial belt in the south have been disrupted since the accident.
The oil spilled into the sea in North East China after two pipelines exploded on Friday night.
The environmental group Greenpeace says the spill is China's worst in recent memory.
In the area around where the pipes caught fire, beaches have been polluted.
An official in the State Oceanic Administration has told Chinese official media that heavy winds on Monday broke up the spill and dispersed it more widely than had previously been reported.
An area of ocean covering 430 sq km is now polluted.
Shipments of oil from the port of Dalian in north-east China, where the pipelines exploded, have slowed.
Reserves in the south are reported to be ample at present - enough to guarantee 10 days' supply - and the oil price in that part of the country is stable.
But the officials leading the clean up warn it could take at least that long to complete their work.
Some reports suggest the winds since Monday have started blowing the oil back towards the shore away from international waters.
That could make the clean up easier, but the environmental impact worse if the oil contaminates more of the coastline.
Every year fishing boats in the area stop fishing from June to August.
Some of their skippers are worried that when they put to sea again in a few weeks, the pollution will have ruined the fishing grounds.
BBC News - China oil spill after pipe blast 'worse than thought'