Photo: AFP/Toshifumi Kitamura

Vanuatu was in a state of mourning on Saturday after its revered president, Baldwin Lonsdale, died unexpectedly. He was 67.

He was rushed to Vila Central Hospital late on Friday night after a suspected heart attack, but died just after midnight.

"Vanuatu has lost one of its greatest leaders," said Sela Molisa, a former long-time parliamentarian who described the late president as a humble, gentle man. "Vanuatu was lucky to have had him."

Flags around the country were lowered to half mast, and hundreds of family, friends and members of the public gathered outside the hospital to stand vigil on Saturday.

The Council of Ministers met to discuss mourning plans, which are likely to include a state funeral, and the late president's body was taken to lie at State House on Saturday night.

Baldwin Jacobson Lonsdale was born on Mota Lava, in the northern Banks islands, in 1950. He grew up to become a senior civil servant and the secretary general of the Torba provincial government before becoming an Anglican priest.

In September 2014, Father Lonsdale was elected to the presidency by an electoral college in the eighth round of voting, when he finally achieved a two thirds majority of MPs and provincial chairs.

Father Lonsdale promised to uphold the constitution and asked the people of Vanuatu to stand united: "I know that there is a big responsibility in the office of the head of state," he said on his appointment.

"But my first and foremost priority is to make sure that the constitution of the nation is upheld at all times and that peace, unity, justice and harmony prevail at all times," he said.

That commitment would come to be tested in a turbulent year in 2015, when the largely ceremonial role would become a pillar of stability through a destructive cyclone and a political crisis.

In March 2015, the country was devastated by Cyclone Pam, a category five storm that swept its way down the archipelago, leaving thousands homeless and much of the country's crops and infrastructure destroyed.

At the time, Father Lonsdale was in Japan at a conference on disaster risk reduction, where he made a tearful appeal for international assistance. "As a nation, as the head of my nation, my heart is for the people," he said in an address that was beamed around the world. "Everyone has that same feeling, because we don't know what happened to our family.

"There's a breakdown of communications that we cannot reach our families and we do not know whether our families are safe or not," he said.

Father Lonsdale described the cyclone as a monster that had wiped out the country's developments, and blamed climate change for contributing to the disaster.

Then, six months later, with the country still rebuilding from the cyclone, another crisis descended upon Port Vila.

In October 2015, 15 MPs -- half the government of Prime Minster Sato Kilman -- was convicted of corruption, making them ineligible for office.

But while Father Lonsdale was overseas, one of the convicted MPs, then-speaker of parliament Marcellino Pipite, pardoned himself and 13 of this colleagues in his capacity as acting president.

A furious Father Lonsdale returned to Vanuatu and rescinded the pardons, before addressing the nation to express his "shame and sorrow" at Pipite's actions.

"I will clean this dirt from my backyard," a visibly shaken president swore in his televised address. "We as a nation have to stop these crooked ways."

Following a failed appeal against the pardons, Father Lonsdale moved to dissolve parliament and called snap elections for January 2016, which saw Mr Kilman's government ousted and a new government formed that promised widespread reforms.

At the opening of the new parliament, Father Lonsdale said "the corruption we have seen is an abuse of public trust for private gain," describing the new legislature as a "new chart for Vanuatu's destiny."

"He was firm and wouldn't be swayed," said Mr Molisa, who said Father Lonsdale's unwavering commitment to the rule of law enshrined him as one of the country's greatest leaders. "History will remember him for this."

"I'm sure the government and every other - especially at the political level - people would recognise that Vanuatu has lost a very outstanding leader," he said.

That was a sentiment shared across Vanuatu. As the news director of the Vanuatu Daily Post, Dan McGarry, said in a post on Facebook: "By shouldering the burden of office, even when others had abused it so, he reasserted the integrity of an office that the Constitutions says embodies 'the unity of the nation'."

"And now, we're all united in mourning. His gift to the nation was immense, and will not be forgotten."

The Prime Minister, Charlot Salwai, was due to address the nation on Saturday evening to announce the nation's plans for a period of mourning. However, government officials said these would likely include a state funeral before the burial of the president's body on Mota Lava.

Under the constitution, the speaker of parliament, Esmon Saimon, is currently the acting president, and a new head of state will need to be elected by another electoral college within three weeks.