Japan is to set aside $10bn (£5.1bn) over the next five years to help developing countries fight global warming, a newspaper has reported.
Some of the aid would go to China, the newspaper said
The aid would aim to cut greenhouse gas emissions in nations like Indonesia and China, the Nikkei business daily said.
Officials confirmed that Tokyo was planning an aid package but said details were still being worked out.
Japan chairs the Group of Eight nations this year and says it will prioritise climate change at this summer's summit.
According to the Nikkei daily, the aid package - to be announced later this month - would be provided in the form of grants or low-interest loans.
As well as emissions cuts, it would be used to tackle disasters caused by global warming and to promote alternative energy sources.
Aid would also be used to help improve the efficiency of China's coal-fired power stations, the daily said.
A government spokesman said that the plan had not been finalised.
"We have yet to decide what the exact contents of the aid package would be and it is undecided when Prime Minister Fukuda will make the announcement," foreign ministry spokesman Takeshi Akamatsu told the French news agency AFP.