Turkish authorities have reinstated over 6,000 teachers suspended after the July failed coup accused of terror links, the education ministry said on Friday.

"6,007 personnel suspended over links to terrorist organisations have returned to their jobs," the ministry said on its official Twitter account.

Tens of thousands of teachers were suspended or sacked over links to Kurdish militants and coup plotters since July 15 when a rogue faction tried to oust President Recep Tayyip Erdogan from power.

Ankara accuses the US-based Islamic preacher Fethullah Gulen and his movement -- which funds many schools across the world -- of masterminding the attempted putsch, but he strongly denies any involvement.

But critics have accused the authorities of using the state of emergency imposed after the coup for a swoop that goes well beyond alleged supporters of Gulen.

Some 11,500 teachers suspected of links to the outlawed Kurdistan Workers' Party (PKK) -- which has waged an insurgency since 1984 -- were suspended in September alone.

The move comes amid reports of teacher shortages that existed even before the suspensions began this summer, in particular in the Kurdish-majority southeast where most of the suspensions took place.

Some union chiefs have expressed alarm over the impact on children's education if inexperienced teachers were forced to be called in as replacements.

Huseyin Ozev, president of the Istanbul teachers' union, said in September, there were 40,000 to 50,000 vacancies. But Ankara said in the same month that by October 10, 20,000 new teachers would start their jobs.

Among the teachers suspended over alleged links to Kurdish rebels, Turkish media said some 9,400 were members of leading education union Egitim Sen, which has 120,000 members in total.

The union's chief Kamuran Karaca told AFP in October that none of his members have links to the coup or terrorism and that they support "secular education, peace and democracy".

Meanwhile, more than 100,000 people in total have been arrested, dismissed or sacked as part of the investigation into the coup bid in a widescale crackdown that has caused alarm in Western capitals.

The country has seen a major upsurge in violence in the southeast with almost daily attacks against Turkish security forces since a fragile ceasefire collapsed last year.