The frontline plant -- seized by Russian forces in the first days of its offensive -- has been in shutdown since 2022 amid frequent shelling attacks.

Grossi was responding to a suggestion by Russia's nuclear operator that the plant be put back online.

"That is not imminent. I have been drawing the attention of my Russian counterparts to the fact that any such action would require a number of considerations," Grossi told AFP.

"First of all, this is an active combat zone, and this cannot be forgotten. Secondly, this plant has been in shutdown for a prolonged period of time," he said.

He did not rule out the plant being put online at some point in the future, but said this would "require a number of safety assessments to be performed".

The power station has been repeatedly rocked by shelling and drone attacks since it was captured by Moscow in March 2022 and requires constant maintenance to prevent overheating.

Grossi said his two main concerns were the physical integrity of the plant and the interruption of its external power supply, which can stop it from cooling properly.

The plant has lost external power eight times since the conflict began, including in December when Ukraine said it was forced to rely on backup diesel generators.