TOKYO - Japanese companies and climate groups called on the nation's government on Wednesday to step up the introduction of renewable energy and quickly adopt carbon pricing to tackle global warming.

The Japan Climate Initiative (JCI), an alliance of companies, local governments and NGOs, issued the message ahead of the meeting of climate ministers of the Group of Seven (G7) countries on April 15-16 in Sapporo where Japan will chair the event to discuss efforts to address climate change.

"We urged the Japanese government to overcome climate crisis and energy crisis by accelerating the introduction of renewable energy and early adoption of highly effective carbon pricing," the JCI said in a statement which was endorsed by 303 organisations.

To achieve a goal which was agreed by G7 last year to decarbonise all or most of the power sector by 2035, Japan should take appropriate measures and implement regulatory reforms to boost renewable energy, it said, urging support for the faster development of offshore wind power and mandatory installation of solar power generation in new buildings.

A transition to clean energy is especially important to the Asian nation, as it is critically dependent on imports for a majority of its energy needs, including for oil to LNG.

Japan aims to cut emissions by 46% versus 2013 levels by boosting renewable energy in its electricity mix to 36%-38%, double of 2019's levels.

But its G7 allies such as Canada, Germany, U.K. and Italy have already reached Japan's 2030 targets, the JCI said.

Japan is introducing a carbon pricing scheme this fiscal year in stages, combining emissions trading and a carbon levy to encourage companies to curb pollution. But the levy will be introduced only from around the 2028/29 fiscal year.

Japan should introduce carbon pricing earlier and more effectively so that the companies' efforts toward decarbonisation are properly recognised internationally, JCI said.

Other climate groups have also expressed frustration with the government's slow action on climate.

"Japan's green transformation plan promotes industry rather than decarbonisation," Kimiko Hirata, executive director of Climate Integrate, told reporters on Tuesday, noting it does not include plans to increase renewables targets.

"Japan has a strong interest in maintaining its existing energy infrastructure. Companies tied to the industry ministry have a lot to gain from the fossil fuel-based energy system."

(Reporting by Yuka Obayashi; Additional reporting by Kate Abnett; editing by Muralikumar Anantharaman and Jason Neely)