ISTANBUL, Turkey -- For the first time in its history, Turkey is directly electing its president on Sunday in a contest considered a turning point for the country of 76 million people -- with its prime minister the strong favourite for a job he has pledged to transform from a symbolic role into one of real power.

Recep Tayyip Erdogan, Turkey's dominant politician over the last decade, is seen by many as aiming to solidify his grip on power after serving three consecutive terms as prime minister at the head of his Islamic-rooted Justice and Development Party. An absolute majority is needed to avoid a runoff on Aug. 24.

The 60-year-old Erdogan is revered by many as a man of the people who ushered in a period of economic prosperity, reviled by others as an increasingly autocratic leader trying to impose his religious and conservative views on a country with strong secular traditions.

His campaign has been bold and bitter. A gifted public speaker, he has poured scorn upon his rivals, casting doubt upon their Turkish identity and even accusing his main challenger of being part of a shadowy coup conspiracy he says is run by a former associate living in the United States.

"This is a critical juncture for democratization," said Ersin Kalaycioglu, political science professor at Istanbul's Sabanci University. "We are not only voting for one guy over another. We're voting for whether Turkey is going to be authoritarian versus whether Turkey is going to improve on its democratic record."

If he wins, many fear he will appoint a pliant prime minister he can control -- and concentrate all true power in his own hands.

Erdogan already tried and failed to change the constitution to give the presidency more clout. But he has vowed to activate latent powers he says already exist for the position, such as calling and chairing cabinet meetings.

"He doesn't seem to appreciate that even if you have the majority behind you, that does not necessarily give you power to do whatever you want," said Ilter Turan, professor of political science at Istanbul's Bilgi University. "In the event he wins, which he appears likely to do, he will push this line to dominate the system."

Erdogan's two challengers are Ekmeleddin Ihsanoglu, a 70-year-old academic who enjoys the support of nearly a dozen opposition parties, including the main republican and nationalist parties; and Selahattin Demirtas, 41, a Kurd who heads a left-leaning party and has already made a name for himself on the minority Kurdish political scene.

A religious man who supports Turkey's deep traditions of secularism, Ihsanoglu headed the Organization of Islamic Cooperation for a decade until this year. In contrast to Erdogan's divisive, often abrasive campaign, he has run on a platform of unity and has promised not to engage in party politics.

"I stand for democracy, for secularism, for pluralism and transparent democracy," Ihsanoglu said after the start of campaigning last month. "I am against the accumulation of power in one hand. I think that would lead to more centralized government and an unwelcomed totalitarian regime that Turks don't want to have."

But while he enjoys the backing of several parties, those parties' supporters have not all united behind the political newcomer.

"The republicans suspected that he was too much religion, the nationalists thought that he was not nationalist enough," said Turan, the political analyst. "But in fact, this is precisely the type of candidate you actually needed, because ... Turkish society is divided right in the middle" between the more pious and conservative, and those with a more secular, Western and liberal outlook.

Demirtas is expected to trail in third place, but could be instrumental in potentially leading the election to a second round by attracting part of the Kurdish vote away from Erdogan. The prime minister has enjoyed support among the minority, estimated at 20 per cent of the population, for relaxing restrictions such as the right to be educated in Kurdish or give children Kurdish names.

There have been several incidents, however, that sparked widespread outrage and potentially put Erdogan's popularity with his electoral base at risk.

The most recent was the mining disaster in the western town of Soma, where 301 miners were killed in a fire blamed on poor safety standards. Erdogan's response was seen as callous, including a dismissive comment about mine accidents being commonplace; images emerged in the media of one of his aides kicking a Soma protester held down by armed police. Anger at his handling of the disaster led to violent protests and calls for his resignation.

Many were also infuriated by his reaction to demonstrations last year, where an environmental protest against his plans to replace central Istanbul's Gezi Park with a shopping mall spiraled into nationwide anti-government protests following a heavy-handed police response. Several people were killed in clashes with police.

Critics also point to what they say was a massively one-sided election campaign where Erdogan used his clout and the funding he enjoys from his premiership to ensure blanket coverage for himself.

"It became a very unfair process from the very beginning," said Kalaycioglu.

Yet Erdogan still commands near adoration from his core supporters -- mainly, but not only, the more conservative and religious Turks who feel he has given them a voice and improved their daily lives with better access to health care, education and infrastructure.

Few doubt he will emerge victorious in these elections.