Voters across the Maldives head to the polls on Saturday for a presidential election aimed at ending a period of political turmoil on the tropical islands following violence last year.

The vote will test the popular holiday destination's young democracy after the ousting in February 2012 of its first elected president, Mohamed Nasheed, who says he was removed in a "coup."

Nasheed, a British-educated scuba-diving fanatic who once held a cabinet meeting under water, is contesting again and is seen as the clear frontrunner among the four candidates.

The man who replaced him in power following a mutiny by the security forces, Mohamed Waheed, is also standing -- along with tourism tycoon Gasim Ibrahim and Abdulla Yameen, the half-brother of long-time Maldivian autocrat Maumoon Abdul Gayoom.

"The atmosphere is ready for free and fair elections," President Waheed told AFP as the candidates wrapped up campaigning on Friday.

"I have given an assurance of my government's full support for anyone who wins the election," he added, speaking from the capital of the nation of around 350,000 people.

If none of the candidates scores more than 50 percent on Saturday, a second round run-off is scheduled for September 28.

Voting will take place from 7:30am (0230 GMT) at 470 polling stations on all inhabited islands as well as on the tourist resorts that have made the country famous as a "paradise" destination.

Nearly one million holidaymakers visited the Maldives last year, drawn to its secluded beaches on private coral-fringed islands where cabins can cost several thousand dollars a night.

Any more instability would spell problems for the industry, the lifeblood of the country, which suffered a wave of cancellations following the unrest last year.

Nasheed resigned from office on national television, which had been taken over by the security forces whom he said threatened him and his family with violence unless he stepped down.

Waheed, who was then vice-president, took the oath immediately afterwards, leading Nasheed to accuse him of taking part in a conspiracy with former dictator Gayoom who ruled for more than 30 years until 2008.

Waheed denies the charges, but the contested change in leadership blemished what was a flourishing democracy in South Asia and has left a legacy of bitterness and distrust.

"We are apprehensive that renegade elements within the police and military... might intervene during voting or during counting," Nasheed told a press conference on Thursday.

His social programmes and activism to highlight the danger of climate change -- 80 percent of Maldivian land is less than one metre above sea level -- earned him plaudits at home and abroad, but he was not universally popular.

After growing frustrated with the judiciary, he sent the army to arrest the head of the country's criminal court which led to a pending criminal charge that he abused his powers while in office.

His work to increase taxes and introduce budget guesthouses earned him enemies among the powerful tourist tycoons, while he is seen by some as being too eager to please neighbouring India.

If he fails to secure a majority in the first round, the 46-year-old is likely to see his three opponents join forces to try to defeat him in the run-off.

Lawrence Gonzi, a former prime minister of Malta who is heading an observer mission to the election from Commonwealth countries, said campaigning had gone smoothly for Saturday's vote.

"The country seems to be prepared but it's not the preparations that count," he told AFP on Friday.

"It's about what happens during the next 48 hours," he said.

UN Secretary General Ban Ki-moon urged the country last week to "ensure that the upcoming presidential elections... will be conducted in a credible and peaceful manner."