A Pacific islander who launched a landmark bid to become the world's first climate change refugee faces deportation from New Zealand after a court rejected his appeal.

Ioane Teitiota, 38, argued that he should not be sent back to Kiribati because rising seas threaten to deluge the island nation, making it unsafe for him and his family.

The Supreme Court acknowledged the tiny nation of about 100,000 people -- which consists of about 30 atolls, most only a few metres above sea level -- was suffering environmental degradation.

But it dismissed Teitiota's application, upholding previous findings that he did not meet the legal definition of a refugee because he would not face persecution if he returned home.

"While Kiribati undoubtedly faces challenges, Mr. Teitiota does not, if returned face 'serious harm'," the Supreme Court said in a ruling released late Monday.

"There is no evidence that the government of Kiribati is failing to take steps to protect its citizens from the effects of environmental degradation, to the extent that it can."

Teitiota moved to New Zealand in 2007 and overstayed his visa, coming to the attention of police in 2011 over a minor traffic violation.

The Supreme Court decision closes his final avenue of appeal in New Zealand. He now faces deportation along with his wife, and their three young children, all of whom were born in Auckland.

Low-lying Kiribati suffers from a range of environmental problems that have been linked to climate change, including storm surges, flooding and water contamination.

The situation is so dire that Kiribati's government has bought 2,000 hectares (5,000 acres) of land in Fiji to act as a farm for Kiribati if salt-water pollution means the former British colony can no longer produce crops.

It has also raised the prospect of relocating the entire population or building man-made islands to rehouse them if predictions that the sea will rise by one metre by the end of the century prove accurate.

The Supreme Court said its ruling on Teitiota did not mean that those affected by climate change would never be recognised as refugees.

"Our decision in this case should not be taken as ruling out that possibility in an appropriate case," it said.