Prime Minister Yasuo Fukuda announced the initiative to protect the environment in a speech at the East Asia Summit, an annual gathering of 16 Asian nations.
"East Asia has experienced rapid economic growth, but it has caused serious environmental problems. I would like East Asia to benefit from Japan's knowledge," Fukuda told reporters.
The centerpiece of the initiative is financial assistance of US$2 billion (EUR1.35 billion) over five years to fight air, water and other pollution.
Fukuda said the initiative is based on three pillars: creating a low-carbon society, conserving rich and diverse nature and promoting global warming education.
The money will be used to train 500 people from countries in the region in proper waste management and other environment protection areas.
Fukuda said the program also aims to conserve forests in East Asia by providing satellite images. Japan will send experts to sites of environmental disasters, he said.
Japan will launch a satellite in 2008 to monitor forests and will share the data.
Japan already gives roughly US$450 million (EUR308 million) in loans and grants to China for environmental programs.
Japan's western coast suffers greatly from air pollution drifting from China, whose industries are 10 times less energy-efficient than Japanese industries, according to the Japanese officials.
The initiative dovetails with another Japanese program called Cool Earth 50, which seeks to halve global carbon emissions by 2050. It was announced by former Prime Minister Shinzo Abe in May and called for an effective framework to address climate change beyond 2012, when the Kyoto Protocol ends.
The Kyoto Protocol is the only international treaty with specific targets. It requires the European Union and 35 other countries to cut emissions by 5.2 percent from 1990 levels by 2012. The United States opted out of Kyoto in 2001, arguing the science was unproven and the burden of mandatory emission cuts was unfair since it excluded fast-growing China and India.