In Indonesia vote, ballots travel on horseback and by boat

It is just one example of the great lengths gone to in the world's biggest archipelago nation, home to some 6,000 inhabited islands and stretching around 5,150 kilometres from east to west, to organise elections.

Months of painstaking preparation culminate in a weeks-long operation, with ballots taken in speedboats out to remote islands, carried on horseback along mountain paths, and in helicopters and small planes to far-flung hamlets.

There will be some 480,000 polling stations set up for the vote across the world's third-biggest democracy.

Some 190 million eligible voters will cast ballots, from the crowded main island of Java -- where more than half of the country's inhabitants live -- to mountainous eastern Papua, and jungle-clad Sumatra in the west.

"Geography is always a problem in Indonesia," election commission spokesman Arief Priyo Susanto told AFP, ahead of this week's poll in which Jakarta governor Joko Widodo and ex-general Prabowo Subianto are in a tight race.

"We distribute logistics to the most remote and least accessible areas first."

The 15 men delivering voting slips on Borneo were from the Dayak tribe, feared in the past for ritually decapitating their enemies then preserving their heads, and they faced a two-day trek over mountains and through the jungle to reach Juhu village.

'Wild boars, blood-sucking leeches'

They ran a gauntlet of wild boars stampeding through the jungle and streams filled with blood-sucking leeches, in areas where there is no phone signal and temperatures plunge at night, local election commission chief Subhani told AFP.

"It's better to walk non-stop for 18 hours than to sleep overnight," added the official, who like many Indonesians goes by one name.

In the Bondowoso district of eastern Java, ballot boxes were being strapped to 20 horses tasked with carting voting slips up precipitous rocky slopes, along deep ravines and narrow dirt paths to highland settlements that vehicles cannot reach.

"It's too dangerous for cars and motorcycles as a wrong move could mean falling to one's death," district election official Juli Suryo told AFP.

In vast Papua, ballots are taken to polling stations by jeep, speedboat and on foot. This year the military is using three helicopters to help with distribution in a bid to speed up the process.

However thick fog in the mountains or heavy rain can hamper delivery of ballot boxes by air. Extra precautions must also be taken if it is raining, with ballot boxes wrapped in plastic sheets and wax paper to protect them.

There have been numerous problems in the country's two direct presidential elections and four legislative polls since the end of authoritarian rule.

These include late arrival of ballot boxes due to bad weather, leaving people to wait several days before they can vote; insufficient voting slips, and ballot papers being sent to the wrong districts.

However, despite the difficulties, most issues are minor, and the majority of voters can normally cast their ballots.

Previous elections have gone well overall, and have largely been considered free and fair, and officials are confident that this year's presidential poll will also pass off without major disruption.