A parliamentary commission has approved constitutional reforms that would substantially increase the powers of President Recep Tayyip Erdogan.

International observers have raised alarm over the prospect of executive powers for Turkey’s increasingly authoritarian leader after tens of thousands of arrests following an attempted coup in July.

The constitutional changes would give the President executive power over Turkish law, allowing him to form a government independently of parliament and appoint his own aides, ministers and deputies, while abolishing the post of Prime Minister.

President Erdogan has capitalised on an attempted coup to oust him in July to accelerate his ambitions for an executive presidency (Getty)

The draft bill also permits the President to maintain ties with a political party, which is banned under the current constitution to maintain the principle of impartiality, while limiting leaders to two terms in office.

The commission approved the draft changes in a marathon 17-hour session that finished on Friday morning, sending 18 new articles for the constitution to a parliamentary vote.

Its decision followed 10 days of tense debate between the committee’s ruling party and main opposition members.

Parliamentary debate on the bill is due to begin in January, with a referendum to follow in spring if it garners the support of at least 330 deputies in the 550-seat assembly.

If more than two thirds of members approve, the changes will be directly passed into law, but the prospect is considered unlikely as Mr Erdogan’s party holds only 317 seats.

His ruling Justice and Development Party (AKP) wants the backing of the Nationalist Movement Party (MHP) opposition to see the plan through parliament.

Turkey's President Erdogan defends government action

Mr Erdogan has rebuffed criticism of widespread purges in the Turkish military, civil service, government, education and media, while attacking reports on the alleged torture and abuse of detainees.

His administration has blamed the coup attempt on the Hizmet movement headed by exiled cleric Fethullah Gülen and claimed those arrested have links to the group, but it has denied involvement and critics accuse Mr Erdogan of attempts to stamp out all opposition.

Opponents fear the proposed reforms would allow the Turkish president, who already exercises unprecedented influence on his party and government, to move further towards authoritarian rule.

Mr Erdogan, 62, came to power in 2002 and spent 11 years as prime minister before becoming the country’s first directly-elected president in August 2014.

He has since turned the supposedly ceremonial role into a powerful platform by drawing on his unrivalled popularity and has long been harbouring ambitions to move Turkey from a parliamentary to presidential system, and regain some of the powers he relinquished.

Amnesty International and Human Rights Watch are among the groups to have raised concern over Mr Erdogan’s increasingly authoritarian style, while the UN cautioned that crackdowns following the coup may violate international law.

Recep Tayyip Erdogan's most controversial quotes Show all 8 1 /8 Recep Tayyip Erdogan's most controversial quotes Recep Tayyip Erdogan's most controversial quotes The Turkish President's craziest quotes Just a week before he was elected President, he called Erdogan Amberin Zaman, the Turkey correspondent for 'The Economist', a "shameless militant woman disguised under the name of a journalist" after she had asked an opposition leader whether "Muslim society is able to question" the authorities. "Know your place," Erdoğan said. "They gave you a pen and you are writing a column in a newspaper. "And then they invite you to a TV channel owned by Doğan media group and you insult at a society of 99 per cent Muslims," he said he said according to Today's Zaman newspaper. Sascha Schuermann/Getty Images Recep Tayyip Erdogan's most controversial quotes The Turkish President's craziest quotes Turkish people are pictured chanting slogans during an anti-government protest on Taksim square in Istanbul, on 29 June, 2013. The protests were sparked by brutal police action against a local conservation battle to save Istanbul's Gezi Park, and soon turned into nationwide demonstrations against the government. Amid the protests - the worst in Turkey for years - Erdogan accused demonstrators of being "arm-in-arm with terrorism," according to Reuters. "This is a protest organized by extremist elements. We will not give away anything to those who live arm-in-arm with terrorism," he said. GURCAN OZTURK/AFP/Getty Images Recep Tayyip Erdogan's most controversial quotes The Turkish President's craziest quotes During last year’s protests, activists used social media to organise and disseminate information. Several dozen tweeters were arrested following the protests, according to local media reports. Erdogan responded by calling the technology a "menace". "There is now a menace which is called Twitter," Erdogan said. "The best examples of lies can be found there. To me, social media is the worst menace to society," BBC New reported. Vladimir Astapkovich/RIA Novosti via Getty Images Recep Tayyip Erdogan's most controversial quotes The Turkish President's craziest quotes Not helping to allay accusations of authoritarianism, after Turkish police detained 49 people, including well-known business people and those close to the ruling party, Erdeogan ominously told reporter that Turkey "is not a banana republic" that can be affected by unnamed "operations", according to Today's Zaman newspaper. “People who are backed by the media and certain funders cannot change this country," he said. "People backed by certain dark gangs both inside and outside Turkey cannot mess with the country's path. They cannot change conditions in Turkey. Turkey is not a country that anyone can launch an operation into. The [Turkish] nation will not allow that. The AK Party, which is governing this nation, will not allow this." Alexander Hassenstein/Getty Images Recep Tayyip Erdogan's most controversial quotes The Turkish President's craziest quotes Friends and relatives of the miners who died in an explosion at the Soma mine are pictured praying following the burial in Soma cemetery of the last body to be recovered from the mine in May 2014. At the time, the then-Prime Minister badly misjudged the Soma mining disaster, in which 301 workers died. He told the relatives of dead and dying miners that "these types of incidents are ordinary things", following allegations that the government had ignored safety concerns about the privately owned mine, the Guardian reported. In his defence, Erdogan recounted in a separate speech a list of mining disasters which occurred abroad, including a British disaster in 1862, and one in America "which has every kind of technology". Oli Scarff/Getty Images Recep Tayyip Erdogan's most controversial quotes The Turkish President's craziest quotes Palestinians pictured attending Friday noon prayers in a destroyed mosque that was hit by Israeli strikes, in Gaza City. As Prime Minister, Erdogan has condemned Israel, accusing it of deliberately killing Palestinian mothers and warned that the it would "drown in the blood it sheds." Speaking to thousands of supporters during a rally in Istanbul ahead of the 10 August election, Reuters reported him as saying: "Just like Hitler, who sought to establish a race free of all faults, Israel is chasing after the same target." "They kill women so that they will not give birth to Palestinians; they kill babies so that they won't grow up; they kill men so they can't defend their country ... They will drown in the blood they shed," he said. AP Recep Tayyip Erdogan's most controversial quotes The Turkish President's craziest quotes Amid the worst protests in Turkey for years which had spread across dozens of cities last June, Erdogan accused demonstrators of being "arm-in-arm with terrorism," according to Reuters. A demonstration to halt construction in a park in an Istanbul square grew into mass protests against a heavy-handed police crackdown and what opponents called Erdogan's authoritarian policies. "This is a protest organized by extremist elements," Erdogan said before departing on a trip to North Africa. "We will not give away anything to those who live arm-in-arm with terrorism," he said. Sascha Schuermann/Getty Images Recep Tayyip Erdogan's most controversial quotes The Turkish President's craziest quotes In March 2014, Erdogan accused a 15-year-old boy who died from injuries sustained in last year's anti-government protests of being linked to terrorism. Berkin Elvan, who became a symbol of anti-government protests, had gone to pick up bread when he was hit with a teargas canister - sending him into a nine-month coma before he passed away. In a speech broadcast on state TV, Erdogan said of Berkin: "This kid with steel marbles in his pockets, with a slingshot in his hand, his face covered with a scarf, who had been taken up into terror organisations, was unfortunately subjected to pepper gas. “How could the police determine how old that person was who had a scarf on his face and was hurling steel marbles with a slingshot in his hand?” ADEM ALTAN/AFP/Getty Images

Wide ranging restrictions on freedom of speech, assembly and association could continue indefinitely under Turkey’s state of emergency, which the president would have executive power to extend under the new law.

“Turkey’s trajectory is toward authoritarianism and the dismantling of all checks on the power of its leaders,” warned Emma Sinclair-Webb, a senior Turkey researcher at Human Rights Watch.

The proposed law would also lower the minimum age of parliamentary candidates from 25 to 18 and increase the number of MPs from 550 to 600 to reflect Turkey’s growing population.

General elections would be held every five years, instead of the current four, with the next round held in November 2019.

A poll conducted by the MAK consultancy found 55 per cent of Turks supported the constitutional changes and would vote “yes” in the possible referendum.