Leaders from 16 countries including the Group of Eight (G8), China, India and Brazil will gather to discuss climate change on the sidelines of the G8 summit in July, Japan's top government spokesman said.

Global warming is at the top of the agenda for the G8 summit and host country Japan is inviting the leaders of Australia, Brazil, China, India, Indonesia, South Korea, South Africa and Mexico to attend an expanded gathering on the topic on July 9, chief cabinet secretary Nobutaka Machimura told a news conference.

"This summit is going to be the largest in history where leaders of many countries will gather," he said.

The eight industrialised nations are meeting between July 7 and 9 on Japan's northern island of Hokkaido, and are expected to discuss 2020 carbon dioxide emission targets, among other issues.

Japan, the world's fifth-largest emitter of greenhouse gases, says part of the solution to curb rising emissions is backing sectoral caps for industries such as steel making and power generation.

But Tokyo's proposal has been met with criticism from Europe and some developing nations such as India at a climate change meeting earlier this week outside Tokyo which brought together 20 of the world's top greenhouse gas emitters.

Mr Machimura also said Japan will host a meeting on African development on July 7.