Prime Minister Robert Abela warned a UN General Assembly summit that the issue of rising sea levels would remain a challenge even if the world honoured its climate change pledges.

Increasing sea levels were a real threat to the Mediterranean region, Abela told a summit in New York, urging everyone's cooperation on the challenge that he said ultimately threatened all of humanity. 

The summit was also addressed by UN chief Antonio Guterres who warned that surging sea levels were creating "a rising tide of misery".

At the summit, a coalition of small island nations declared that their sovereignty must be respected even if their lands are subsumed.

Nearly a billion people worldwide live in low-lying coastal areas, increasingly vulnerable to storm surges, coastal erosion and flooding - while Pacific islands face growing threats to their economic viability and even existence.

According to Abela, the challenge of rising sea levels had widespread economic implications with small states like Malta being at the frontline.