Prime Minister of the Solomon Islands Manasseh Sogavare has condemned Japan's decision to start releasing the nuclear-contaminated wastewater from the crippled Fukushima Daiichi nuclear power plant into the Pacific Ocean.

The prime minister of the Pacific island country made the remarks while attending the Melanesian Spearhead Group (MSG) Leaders' Summit held in Vanuatu's Port Vila, along with ruling party leaders from Vanuatu, Papua New Guinea, Fiji and New Caledonia.

A press release from the Prime Minister's Press Secretariat earlier in Thursday said Sogavare "delivered a strong statement against Japan's decision to release nuclear treated water into our ocean which has an impact on our people, ocean, economy and livelihood."

Participants of the MSG meeting will decide on a number of important matters concerning the MSG region, one of them being Japan's plan to dispose nuclear-contaminated wastewater into the Pacific Ocean, according to the press secretariat.

Japan's ocean discharge plan of the nuclear-contaminated wastewater has met with strong opposition and criticism both at home and abroad, including from Pacific island countries whose economies rely heavily on fishing .

Vanuatu's Foreign Minister Matai Seremaiah has said Japan's decision needed robust actions, urging polluters to "seriously consider other options."

Seremaiah said they were pushing for a declaration for the whole MSG group to denounce Japan for putting anything into the Pacific Ocean until they are absolutely clear that there's no danger.

On Thursday, live video provided by Tokyo Electric Power Company (TEPCO), the operator of the Fukushima Daiichi nuclear power plant, showed the ocean discharge of the first batch of the plant's radioactive wastewater has started as scheduled. The discharge commencement date was in a decision announced by the Japanese government on Tuesday.

Hit by a massive earthquake and an ensuing tsunami in March 2011, the Fukushima nuclear power plant suffered core meltdowns and generated a massive amount of water tainted with radioactive substances from cooling down the nuclear fuel.