United Nations chief Ban Ki-moon says he has seen firsthand the need for urgent action on climate change after visiting the remote Solomon Islands.

During his one-night stay, Ban said rising sea levels are wiping out crops on low-lying islands in the Solomons and threatening the existence of the entire chain, located 1,200 miles northeast of Australia.

"The ocean is already destroying crops in low lying atolls like Ontong Java. That puts food security at risk. Poor food security means weak social stability," said Mr Ban Ki-moon.

"Multiple tsunamis are pounding the islands and the economy. The United Nations and the Solomon Islands Government have worked together to address these emergencies but to really reduce the risks, we need international action."

Ban said Sunday that he's ready to "sound alarm bells to the whole world" over the dangers of climate change. He said the developed world has a moral obligation to help nations like the Solomons with financial and technological aid.

Ban left for Kiribati on Sunday, another island chain threatened by climate change. From there, he will fly to New Zealand to attend the Pacific Islands Forum Leaders meeting.