By Chris Hogg
BBC News, Tokyo
Japan has decided it will allow inspectors from the International Atomic Energy Agency (IAEA) to check its damaged nuclear plant.
The plant suffered more than 50 malfunctions because of the quake
Last week the Japanese government rejected an offer from the IAEA, but this decision has now been reversed.
Meanwhile the company that runs the nuclear plant in Niigata has said it may not even be able to begin checks of the reactor cores until September.
The plant was damaged when a strong earthquake struck the area last week.
When the IAEA first offered to dispatch experts to inspect the damaged plant, Japan said they were not needed. It said Japanese officials could handle the safety check on their own.
But local officials in Niigata asked the government to reconsider.
They said bringing in outside experts would help to damp down rumours that the radiation leaks last week had been more serious than the plant's operators had admitted.
Now ministers in Tokyo have changed their mind. The inspectors will be allowed in.
Both sides are describing the mission as an opportunity to share information with the international community - a face-saving formulation.
Japan says it hopes other countries will benefit from the lessons learned.
But from the plant's operators, the Tokyo Electric Power Company, there is more evidence of just how long this might take.
Safety checks on the reactors probably will not begin before September, they said, because contaminated water that has leaked inside one reactor needs to be cleaned up first and dozens of other problems need to be fixed.
A spokesman for the company said they had had their hands full dealing with the problems caused by the earthquake last week.
They said they were nowhere near the point where they could draw up a detailed timetable for safety checks.