TURKISH President Recep Tayyip Erdogan will gain sweeping new powers over the budget and legislation following a nation-wide referendum, results suggest.

Polls closed at 5pm local time on 18 constitutional changes replacing the country’s parliamentary system of government with a presidential one.

The changes will abolish the office of the prime minister and give Erdogan, who survived a failed coup last year, authority to declare a state of emergency without parliamentary approval, as well as the power to draft the budget and issue decrees overseeing ministries.

Around 55 million people were eligible to take part in the vote, which followed a number of arrests of journalists and activists, prompting international outcry about the treatment of government critics.

Opinion polls suggested a slim lead as the ballots opened, and exit polls showed Yes led No.

Erdogan and his supporters claim the “Turkish-style” system will bring stability and prosperity to the country following the coup bid and a number of terrorist attacks by Daesh.

The country is also tackling Kurdish militants and has been criticised by human rights organisations for its treatment of the minority ethnic group.

The changes could allow Erdogan to remain in power until 2029, and opponents fear the powers could lead to autocratic one-man rule.

Kemal Kilicdaroglu, the leader of Turkey’s main opposition party, hoped for a No vote before voting opened, stating: “We hope the results will be good and together we can have the opportunity to discuss Turkey’s other fundamental problems.”

However, casting his vote in capital city Istanbul, the president called the referendum an opportunity for the “transformation” of the country, adding: “We need to make a decision that is beyond the ordinary.”

Security around polling stations was tight, but an incident outside one site saw three people die.

Two people were arrested after the incident and the state-run Anadolu news agency said it may have been triggered by a dispute over land, but the private Dogan news agency reported it as caused by “differences in political opinion”.

Erdogan, 63, came to power in 2003 as prime minister, a role he retained until becoming the country’s first directly elected president in 2014.

The changes, set to come into effect with the next general election in 2019, set a limit of two five-year terms for presidents and also allow leaders to remain at the helm of a political party.