MANILA - President Rodrigo Duterte lamented Friday the effects of climate change on developing countries like the Philippines, saying it affects the "poorest of our poor" the most.

Duterte, who is in Tokyo for a 4-day working visit, questioned international policies in relation to climate change.

"Vulnerabilities are not equally shared by all nations. Developing countries that have contributed the least of global warming, like my country, the Philippines, suffers the most from this horrendous consequences,” he said in his keynote address at the 25th International Conference on the Future of Asia.

“Year in, year out, we suffer double when typhoons strike. The poorest of our poor bear the brunt of damage, becoming even poorer in the aftermath. Government with limited resources and capabilities have to contend with a spiral of suffering on top of the urgent development priorities,” he said.

The Philippines is among nations most vulnerable to climate change. It constantly deals with heavy monsoon rains and is battered by an average of 20 typhoons per year.

While Duterte affirmed Manila's intent to join the global consensus against climate change, he lamented the lack of sanctions for big polluting countries.

"What is the system? What is this conference of climate change for? Is it just talk? Because there is no body, no entity to enforce the laws governing climate. There is not even a sanction," he said.

The Philippines, under Duterte, is a party to the Paris Agreement on Climate Change, which aims to slash greenhouse gases and keep global temperature increases to "well below" 2 degrees Celsius.

He earlier expressed misgivings about the climate pact, saying it favored industrialized countries.

Under the accord, Manila promised to cut carbon emissions by 70 percent by year 2030, even if the country is not a major emitter.