An International Atomic Energy Agency (IAEA) task force held a press conference on Friday following its five-day mission in Japan to review the controversial planned release of treated water from the Fukushima nuclear plant into the ocean.

The task force has collected and been examining the treated water samples during their first mission to Japan this week to evaluate the safety as well as the radiation effects, on both humans and the sea itself, of discharging the treated water from the Fukushima nuclear plant into the sea. 

The mission this week is the first mission for the IAEA task force among many to thoroughly review the plan for water discharge. The IAEA said they made great progress this week as they built up a deeper understanding on the nuclear plant's operation and its infrastructure.

They also examined safety-related documents including water discharging process and environment assessment, as well as provided advice for Tokyo Electric Power Company (TEPCO), the plant operator on related issues.

This week's research result will be included in the report, which is expected to be released at the end of April, according to the IAEA at the virtual conference.

The experts from the task force are from different countries in a bid to provide reviews from different angles and to be as much objective as they can.

The IAEA said their goal is to provide an objective, science-based review and ensure the activity will be conducted in a safe, transparent manner.

More than a million tonnes of processed water has accumulated in tanks at the crippled plant since it went into meltdown following a tsunami in 2011 and storage space is running out.

The liquid includes water used to cool damaged reactors, as well as rain and groundwater that has seeped into the area.

The controversial decision on dumping the treated water to the sea provoked intensive concerns from local fishermen and international opposition as Japan said the discharge will start around spring 2023.

The task force will carry out other missions in Japan, regarding regulatory activities and environment monitoring. 

IAEA said the task force will continue their examination as "the work is still in progress."