ISTANBUL - Prime Minister Recep Tayyip Erdogan is Sunday expected to vanquish his two rivals in elections to become the next Turkish president, promising to expand the post with new powers as opponents worry Turkey is creeping towards autocracy.
Erdogan, a pious Muslim, has ruled Turkey as premier since 2003, a period in which he has transformed the country with modernisation projects but also faced accusations of a gradual Islamisation and an erosion of civil rights.
Polls opened at 0500 GMT and are due to close at 1400 GMT.
The polls are the first time Turkey will directly elect its president, who has previously been chosen by parliament and in recent decades has fulfilled a largely ceremonial role.
However Erdogan, who is happy to be referred to by followers as the "Sultan", has made clear he intends to be a head of state who "sweats" and exercises real power.
His ruling Justice and Development Party (AKP) has vowed to seek to change the constitution to give the president more powers, which could give Turkey a presidential system similar to France rather than its current parliamentary democracy.
Yet his opponents accuse Erdogan of undermining the secular legacy of Turkey's founding father Mustafa Kemal Ataturk, who based the modern state after the collapse of the Ottoman Empire on a strict separation between religion and politics.
'National will, national power'
Opinion polls predict that Erdogan will easily win over 50 per cent of votes to take Ankara's Cankaya presidential palace in the first round, with his main opposition rival Ekmeleddin Ihsanoglu lagging far behind in second place.
"There really is no uncertainty about this outcome. It's almost a foregone conclusion that Erdogan will win," said Sinan Ulgen of the Carnegie Centre.
While many secular Turks detest Erdogan intensely, he can still count on a huge base of support from religiously conservative middle-income voters particularly in central Turkey and poorer districts of Istanbul who have prospered under his rule.
"We will write the history of the new Turkey on August 10," he told tens of thousands of cheering supporters in Ankara in one of his final election rallies.
Out of a population of some 76 million, 53 million voters were to cast their ballots at more than 165,000 pollings stations.