Safeguarding Tuvalu's future against rising sea levels has come some way to fruition after New Zealand/Aotearoa pledged an additional $20 million towards developing flood resilience works on the smallest sovereign island-state on the planet.

According to figures from the New Zealand Ministry of Foreign Affairs and Trade's DevData website, the latest contribution for the Tuvalu Coastal Adaptation Project more than doubles the foreign government's aid to the Pacific island nation for the 2025-26 financial year.

The Tuvalu Coastal Adaptation Project is an implementation of measures which reduce exposure to coastal hazards across the nation state's three key islands, developing a long-term coastal adaptation strategy, building up capacity for local national authorities to best implement adaptation actions, and to invest in youth as future stewards for a culturally-resilient people.

A need for the project comes following a combination of intensifying cyclone events, which in combination with accelerated sea-level rises is expected to have a significant impact on Tuvalu's existence.

The updated partnership agreement was signed in Auckland amid ongoing discussions between host Prime Minister Christopher Luxon and his Tuvaluan counterpart Feleti Teo.

In confirming the arrangement — which is largely pulled together through the Green Climate Fund and managed by the United Nations Development Program with the Tuvaluan government — Mr Luxon said he has "huge admiration" for Tuvalu's resilience in the face of stern climate challenges.

Financed with $52 million from the Green Climate Fund and with nearly $2.5 million from its own government, the project will enable Tuvalu to take steps to manage the growing assortment of risks from the coastal hazards.

"(Tuvalu) is leading the way globally in responding to sea-level rise, and we are incredibly proud to support Prime Minister Teo's globally renowned land raising and coastal protection efforts," Mr Luxon said.

"We know that the outcomes for our people and our region depend on that resilience ... New Zealand stands ready to help provide practical support."

More than 6500 Tuvaluans finding comfort living in New Zealand, easily Tuvalu's largest diaspora in the world, as the Pacific Ocean gradually encroaches on their homeland.

Mr Teo responded by saying any further sea-level rise is set to have a "devastating impact" on his nation's territory, which consists of three reef islands and six smaller atolls.

"As you will know, Tuvalu is an atoll-island nation - it is totally flat," he said.

"I have spoken in many international arenas, advocating for countries to continue to recognise our sovereignty and the permanency of its maritime boundaries despite the impact of sea-level rise."

The threat to Tuvalu's tiny land mass may affect it's sovereignty.

Tuvalu could lose its legal status as an independent nation should too much land area become submerged, which has also become the subject of its frequent diplomacy in recent years.

A projection which the UN has widely circulated estimates around 95 percent of Tuvalu's surface area of just 26.26 km2 across all nine parcels of its land could be underwater by the turn of the next century.

Tuvalu has been forced to reclaim land near its capital, Funafuti, to maintain its relevancy and in support of its more than 10,000 residents.

Acting on this dilemma, Tuvalu has sought treaty agreements with several wealthy international partners, including Australia, and more controversially, Taiwan.

As part of its Falepili Union treaty with Canberra, Tuvalu has secured "climate mobility" visas for up to 280 Tuvaluans, or roughly 2 percent of the nation's population each year, which included the first arrivals landing in Australia earlier this year.

Tuvalu also committed to a mutual security pact with the Australian government in the deal over an associated partnership or other arrangements along the lines of defence and security.

Late last year, Tuvalu struck a Kaitasi Treaty with Taiwan to guarantee full recognition of its own Republic of China sovereignty at a time of significant Chinese influence in the region.

The People's Republic of China has consistently refused to hold diplomatic relations with countries who simultaneously recognise the sovereignty of Taiwan.

Tuvalu is one of three Pacific nations, which include Palau and the Marshall Islands, which has stood defiant against Beijing's wishes.

New Zealand had been in discussions over the prospect of its own treaty with Tuvalu by 2028.

Tuvalu is hoping to secure the treaty in time for its 50th independence anniversary the following year.