Turkey's ruling party is expected to name Prime Minister Recep Tayyip Erdogan as its candidate in August presidential polls Tuesday, putting him on the path to become the longest serving leader since the country's modern founder Mustafa Kemal Ataturk.

Erdogan's Justice and Development Party (AKP) is due to end months of speculation by announcing its candidate at Ankara's Chamber of Commerce, but there is little suspense left.

Taking the presidency would allow Erdogan to extend an extraordinary 11-year period in power that has already seen him tame the military, return Islam to public life and oversee rapid economic growth.

At a time when he is increasingly under fire from opponents for ruling like an Ottoman autocrat, the presidency would see him stay in power until at least 2019. This would make him the country's longest serving leader since Ataturk who was president for 15 years after establishing the modern Turkish republic.

Statements by top AKP ministers have all but confirmed Erdogan's candidature already, as incumbent President Abdullah Gul said he would step aside.

"Prime Minister Erdogan is very likely to be our candidate," said Deputy Prime Minister Bulent Arinc.

"If God allows us, the nomination of our prime minister will most probably be announced," he said.

The election on August 10 -- followed by a second round if required on August 24 -- will be the first time ever that Turks have directly elected their president. Previously, the president has been chosen by parliament.

Over the past year, Erdogan has endured one of the most turbulent periods of his rule with violent street protests across the country and vehement criticism of his government's handling of the Soma mine disaster in May that killed 301 workers.

Also with a vast corruption scandal that went to the heart of Erdogan's party and family, critics say his uncompromising stance has left Turkish society more polarised than ever.

Secular segments of society fear the country is sliding towards autocracy.

But Erdogan has fought back, accusing his erstwhile ally Fethullah Gulen, a Muslim cleric exiled in the United States with widespread influence over Turkey's police and judiciary, of orchestrating a plot to unseat his government.

Despite his recent difficulties, the premier retains a strong bedrock of support particularly among rural Turks and pious small business owners.

An overwhelming victory in local elections in March demonstrated that the recent crises had done little to damage Erdogan's standing among these crucial constituencies.

Meanwhile, the opposition presidential candidate, Ekmeleddin Ihsanoglu, a former head of the Organisation of Islamic Cooperation, has none of the premier's charisma.

"The Turkish nation would not give the title of president to a candidate that they learned about from Google," Justice Minister Bekir Bozdag said.

If Erdogan ascends to the presidency, he is expected to make the post far more than the largely ceremonial role fulfilled by Gul, who said on Sunday he would leave high office for good.

A recent survey by pollster Genar predicted Erdogan would win an outright victory in the first round on August 10 with 55.2 percent of the vote against Ihsanoglu on 35.8 percent.

After three terms as prime minister -- the maximum allowed under the AKP's own party rules -- Erdogan has made no secret of his ambitions.

His party has won every election since coming to power in 2002, presiding over strong economic growth over the last decade.

"It will not be a president of protocol, but one that sweats, runs around, works hard," Erdogan said in April.

Gul tried to be a unifying and moderate voice but earned the moniker of "Notary" after rubber-stamping government bills.

"I will not present my candidacy... my term expires on August 28," Gul told reporters, further raising the likelihood that Erdogan would run for the top job.