Prime Minister James Marape said he was "greatly concerned" for his country and other Pacific island nations threatened by rising seas and severe weather patterns.

"I ask President Trump to reconsider his decision to withdraw USA from the Paris Agreement," Marape said.

"The United States is the second biggest holder of carbon footprint, only after China," he said in a statement.

"The United States is not shutting down any of its coal power plants yet decides to withdraw from current climate efforts. This is totally irresponsible."

Marape said the United States had recently "revitalised" its relations with countries in the Pacific region, where it vies with the growing diplomatic and military influence of China.

It was "very discouraging" that the United States was quitting climate talks, the prime minister added.

"President Trump has his rights in his Put America First agenda, but he needs to tell us how he will respond to the matter of climate change because the Science is not lying to us about the planet heating up," he said.

"It is morally wrong for him not to be sensitive to the global climate change issues."

Marape said he would raise Trump's decision with fellow members of the Pacific Island Forum, a grouping of 18 countries and territories in the region.

As Trump took office on January 20, he announced the United States' withdrawal from the 2015 Paris accord adopted by 195 parties to curb greenhouse gas emissions.

Papua New Guinea is among a group of at-risk Pacific countries that have asked the International Court of Justice in The Hague for a legal opinion on countries' obligations to protect against climate change.