Tuvalu's Prime Minister Enele Sopoaga has cast an outsize role in the Pacific's battle against climate change, putting the island nation — no bigger than half of Melbourne's CBD — on the map in the process.

Key points: Tuvalu's 16-member parliament welcomed seven new MPs in recent elections

Tuvalu's 16-member parliament welcomed seven new MPs in recent elections New PM Kausea Natano has held ministerial positions and wants climate change action

New PM Kausea Natano has held ministerial positions and wants climate change action His election has led to speculation about Tuvalu's continued alliance with Taiwan

But on Thursday his premiership came to an end, following a vote in the country's Parliament — made up of 16 MPs.

Mr Sopoaga lost by 10 votes to 6.

Replacing him will be Kausea Natano, Tuvalu's longest-serving MP, who has previously held ministerial appointments in communications, transport, and public utilities.

Mr Sopoaga — who last month stared down Australian Prime Minister Scott Morrison at the Pacific Islands Forum (PIF) — had been prime minister since 2013, but a recent national election saw several of his ministers ousted.

The poll saw the election of seven new MPs — replacing just under half of Tuvalu's total MPs.

Government secretary Tine Leulu told the ABC's Pacific Beat program that by Saturday, the new parliamentary composition had implied there was going to be a shakeup of Tuvalu's leadership.

"A lot of people had been speculating that the 10 had set up a tentative line-up of ministers," Mr Leulu said.

"Everyone is glad that it's over now — people have been speculating since Saturday."

Who is Kausea Natano?

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 2 minutes 37 seconds 2 m 37 s What you need to know about Tuvalu.

Mr Natano is an MP for the electorate of Funafuti, which sits in the Tuvaluan capital of the same name.

Mr Leulu told the ABC the new PM had previously served in the country's Customs Department prior to his parliamentary debut.

The new PM has been a high-profile champion for action on climate change, co-chairing the UN climate change summit in 2014.

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Tuvalu, along with a string of small Pacific island states, has pressed Canberra to hasten its emissions-reductions efforts, maintaining that the region's low-lying islands and atolls are vulnerable to rising sea levels caused by climate change.

This came to a head at last month's PIF, where Australia stymied efforts by Tuvalu and other Pacific nations to release a unified communique calling for greater climate change action.

Speaking to reporters after the forum, Mr Sopoaga highlighted his terse exchange with Australian Prime Minister Scott Morrison over climate change.

"We expressed very strongly during our exchange, between me and Scott [Morrison], I said: 'You are concerned about saving your economy in Australia … I am concerned about saving my people in Tuvalu,'" Mr Sopoaga said at the time.

Currently, Tuvalu is the chair of the Pacific Islands Forum, and Mr Sopoaga was expected to play a major role at the UN's Climate Action Summit in New York on Monday.

But Mr Leulu told the ABC a cabinet meeting held late on Thursday would determine who would be sent over.

'Taiwan will be very nervous about this'

Taiwan President Tsai Ing-wen counts many allies in the South Pacific. ( Supplied: Office of the President of Taiwan )

But speculation has mounted on the new government's position on Tuvalu’s diplomatic recognition of Taiwan.

This week, Tuvalu's neighbour the Solomon Islands cut ties with the Asian territory, which left Taipei with a total of 16 diplomatic allies worldwide.

China believes Taiwan is a rogue breakaway territory — and claims it in its entirety — though a small number of South Pacific, Caribbean, Latin America countries, and the Vatican recognise Taiwan's independence.

A war of alliances has intensified in recent years, as Beijing has managed to poach allies such as Burkina Faso, the Dominican Republic, Sao Tome and Principe, Panama and El Salvador from Taipei in recent years.

The Solomons' decision is believed to be motivated by Beijing outbidding Taiwan's aid contributions in the form of a "development fund" — while unclear how much, various Chinese and Taiwanese media outlets reported Beijing pledging $730 million.

Following the loss of the Solomon Islands, Taiwan now has a total of 16 allies worldwide. ( ABC News: Jarrod Fankhauser )

Regional analysts said the change in power in Tuvalu could give Beijing an opportunity to further isolate Taiwan.

"It wouldn't take much cash to get Tuvalu to consider its position," Jonathan Pryke, director of the Pacific Islands program at the Lowy Institute, told Reuters.

"Taiwan will be very nervous about this outcome."

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 5 minutes 13 seconds 5 m Australia's ex High Commissioner to Solomon Islands, James Batley, says the nation's move to side with China was not surprising.

This wasn't a view shared by Taiwan's ambassador in Tuvalu, Marc Su, who said Beijing had little influence in Tuvalu after an unsuccessful attempt to draw the country away just over a decade ago.

"You can feel they are trying to attract our diplomatic allies in every possible way," Mr Su said.

"This country is OK — there won't be any effect," Mr Su said, adding Taiwan had good relationships in Tuvalu, from "grass roots to top level".

Taiwan will contribute $10.4 million to Tuvalu's budget in 2019, according to budget documents.

Along with aid, the nation of around 12,000 people is heavily reliant on income derived from the sale of fishing licences to foreign trawlers and revenue generated from its fortunate country code domain name, ".tv".

The domain name attracts interest from many media companies and websites around the world which pay for the rights to use it.

ABC/Reuters