Around 6,500 employees of Turkey's education ministry have been suspended, a Turkish official said, as a probe launched after a failed coup into the military, civil service and schools gathers pace.

The latest suspensions came a day after the same ministry suspended 15,200 personnel and also revoked the licences of 21,000 teachers working in private institutions across Turkey.

So far about 60,000 soldiers, police, judges, civil servants and teachers have been suspended, detained or are under investigation following the military coup attempt last weekend.

Academics have been banned from travelling abroad in what a Turkish official said was a temporary measure to prevent the risk of alleged coup plotters in universities from fleeing. State TRT television said 95 academics have been removed from their posts at Istanbul University alone.

"Universities have always been crucial for military juntas in Turkey and certain individuals are believed to be in contact with cells within the military," the official said.

President Tayyip Erdogan blames the network of U.S.-based cleric Fethullah Gulen for Friday night's attempted coup, in which more than 230 people were killed as soldiers commandeered fighters jets, military helicopters and tanks to try to overthrow the government.

Erdogan has vowed to clean the "virus" responsible for the plot from all state institutions. The depth and scale of the purges have raised concern among Western allies that Erdogan is trying to suppress all dissent, and that opponents unconnected with the plot will be caught in the net.

In a sign of how shaken Turkey's leadership has been by the coup attempt, with dozens of generals arrested as well as Erdogan's aide de camp, government ministers and top officials have not been briefed in advance of the meetings.

"The cabinet meeting is classified at the highest level for national security reasons. The palace will give ministers a dossier just beforehand," one senior official told Reuters.

"Ministers do not yet know what is going to be discussed."

Around a third of Turkey's roughly 360 serving generals have been detained since the coup attempt, a second senior official said, with 99 charged pending trial and 14 more being held.

The defence ministry is investigating all military judges and prosecutors, and has suspended 262 of them, while 900 police officers in the capital Ankara were also suspended. The purge also extended to civil servants in the environment and sports ministries.

The threat of prolonged instability in a NATO member country, which had not seen a violent military coup for more than three decades, has shaken investors' confidence.

The lira hit a 10-month low in early trade on Wednesday, touching 3.063 to the dollar before recovering slightly. The Istanbul stock index is down 9.5 percent so far this week, its worst three-day performance since 2013. The cost of insuring Turkish debt against default rose to its highest in nearly a month, according to data from Markit.

Deputy Prime Minister Mehmet Simsek told Reuters a priority in the measures to be discussed on Wednesday would be preventing damage to the economy. He also said on Twitter they would be "market-friendly" and would prioritise structural reform.

MILITARY CHIEF REFUSED TO BACK COUP BID

Around 1,400 people were wounded as soldiers on Friday commandeered tanks, attack helicopters and warplanes, strafing parliament and the intelligence headquarters.

At the height of the abortive coup, the rebel pilots of two F-16 fighter jets had Erdogan's plane in their sights as he returned to Istanbul from a holiday on the coast. Erdogan said he was almost killed or captured by the mutineers.

In testimony published by the Hurriyet newspaper and corroborated by a Turkish official, an infantry lieutenant-colonel said the coup plotters had tried to persuade military chief Hulusi Akar, who was being held hostage, to join the effort to overthrow Erdogan but that he had refused.

"When he refused, they couldn't convince the senior commanders either. Akar's refusal to be a part of this paved the way for the failure of the coup attempt," the written transcript published by the newspaper said. .