Turkey's ruling party on Sunday reappointed President Recep Tayyip Erdogan as its chief after a nearly three year break, swiftly exploiting a key change agreed in a controversial referendum on expanding his powers.

In a precisely choreographed special congress in Ankara, the ruling Justice and Development Party (AKP) elected Erdogan -- the only candidate -- to replace Prime Minister Binali Yildirim as chairman.

Erdogan had rejoined the AKP on May 2 after a slim majority of voters on April 16 approved sweeping changes to create an executive presidency, which critics fear could lead to one-man rule.

Under the old constitution, the head of state had to sever ties with their political party and Erdogan in August 2014 left the AKP and stepped down as chairman after his election as president.

Taking the reins of the party will give Erdogan day-to-day control over its decision making, appointments and strategy as it prepares for elections in 2019.

It also gives Erdogan responsibilities unmatched by any Turkish leader since 1950, with more new powers to come when the other changes agreed in the referendum to take effect from 2019.

Thousands of supporters from across Turkey crammed into the Ankara sports arena gave Erdogan a rock star-like reception at his first major party event since 2014.

"We are together again after three years," Erdogan said in his candidate speech. "Our hearts were not divided... we lived as one heart."

With the outcome of the vote a foregone conclusion, AKP deputy chairman Hayati Yazici announced Erdogan received 1,414 votes, to cheers from the audience.

In a thank you speech, Erdogan vowed the congress would mark a "new start" for Turkey.

"In the next few months, from the fight against terror to the economy, from expanding rights and freedoms to investments, in every field, this new period will be a leap for Turkey."

Rejoining the AKP was the first major change permitted after the referendum, which Erdogan narrowly won with 51.4 percent of the vote.

Most measures, including axing the role of premier and giving the president the power to appoint ministers, will not come into force until elections on November 3, 2019.

Yildirim, who is staying on as prime minister, will be given a newly-created role of vice chairman, Yazici said.

Erdogan led the party for three terms during his premiership between 2003 and 2014, helping build the AKP into an all-conquering election machine that has yet to be defeated at the ballot box.

The father-of-four describes the AKP -- the most effective Islamic rooted-political force in the history of modern Turkey -- as his "fifth child".

The move comes with Turkey at a critical juncture after the July failed coup -- which was followed by an unprecedented crackdown -- and at a time of growing tensions with the West.

Erdogan warned that the state of emergency imposed after the coup "won't be lifted until there is peace and prosperity".

He also called on the EU to make clear if it truly wants Turkey as a member. "We are not forced to be patient with the EU's two-faced attitude... the EU needs to make a decision."

A special congress slogan read "a new breakthrough period: democracy, transformation, reform", hinting at a restructuring of the government as well as changes to the party's executive in the coming weeks and months.

"By the end of this year, all our institutions will have a serious renewal," Erdogan said.

In a sign of the controversy generated by the changes, police on the Asian side of Istanbul used tear gas and batons to disperse a protest of around 100 people against Erdogan's new powers, an AFP reporter said.

It is the first time the president of Turkey holds the post of both party chairman and head of state since the end of the presidency in 1950 of Ismet Inonu, the successor and right-hand-man of Mustafa Kemal Ataturk, Turkey's modern founder.

As AKP leader, Erdogan can decide the party's direction as it prepares for March 2019 local elections and then simultaneous legislative and presidential elections in November that year.

According to Aykan Erdemir, senior fellow at the Foundation for Defense of Democracies, becoming chairman would mean Erdogan gains the "formal authority to determine who runs for office from AKP lists".

"This new prerogative will allow him to design both a party apparatus and a parliamentary group composed entirely of loyalists."