An Istanbul court on Monday slapped world-renowned pianist Fazil Say with a 10-month suspended jail term for blasphemy in what the musician has said was a political case instigated by Turkey's ruling party.

The court handed down the sentence after finding Say guilty of "insulting religious values of a part of the population" in a series of tweets that critics said insulted Islam and Muslims. The pianist was not present in court during the sentencing.

Say has accused the AKP, the ruling Justice and Development Party, of being behind the case against him.

Say, an atheist, has often criticised the Islamist-rooted party, accusing it of having a secret agenda to promote conservative values in Turkey.

The 43-year-old virtuoso, who has played with the philharmonic orchestras of Berlin, New York, Tokyo and Israel, was charged with inciting religious hatred and insulting Islamic values in a series of tweets.

The charges relate to tweets from April last year, including one where he said: "I am not sure if you have also realised it, but all the pricks, low-lives, buffoons, thieves, jesters, they are all Allahists."

He had faced a maximum sentence of 18 months.

The case stoked fears of growing restrictions on freedom of expression in a country which has long sought to join the European Union.