"We can cooperate if the government of Japan so decides and invites us. We could cooperate in the whole spectrum of the operation, before, during and afterwards", Grossi said during an interview with the agency, which was published on Sunday.
The Japanese government has looked for ways to dispose of radioactive water from the crippled nuclear power plant as storage space at the facility is expected to run out in 2022. South Korea and China are among the countries to have expressed their disapproval of proposals to release the water into the environment.
"Regulated discharge to the open sea or evaporation, are technically feasible", Grossi said, adding that the IAEA was in "preparatory talks" with the Japanese government.
The agency also plans to host an international conference to mark the 10th anniversary of the Fukushima nuclear disaster, which took place on 11 March 2011.
The facility was heavily damaged after a 9.0-magnitude earthquake in the Pacific Ocean triggered a massive tsunami that hit the plant and caused three nuclear reactors to melt down.