The Japanese industry ministry will announce its proposal to boost the use of coal by rolling back rules that were aimed at curbing greenhouse gas emissions, Jiji Press and other Japanese media reported, citing unnamed sources.

Power suppliers have previously been required to keep the operating rate of coal-fired thermal power stations that emit large amounts of carbon dioxide at or below 50 percent, according to Jiji Press.

But the government now intends to allow full operation of older, less efficient coal-fired plants, the report said, adding the ministry will present the plan at a panel of experts' meeting scheduled for Friday.

The initiative follows many Asian nations' pivot towards coal to power their economies as the crucial Strait of Hormuz energy trade route remains partially closed by Iran during the Middle East war that started late last month.

South Korea plans to lift a cap on coal-powered generation capacity, while also increasing nuclear plant operations.

The Philippines also intended to boost the output of its coal-fired power plants to keep electricity costs down as the war wreaks havoc with gas shipments.

Japan relies on thermal power plants to generate around 70 percent of its electricity needs, with coal serving as a major fuel to run them.

Japan on Thursday said it had also started to release another part of its strategic oil reserves, as it faced supply challenges to its oil imports, 90 percent of which normally come from the Middle East.