Turkish media linked to an influential cleric opposing President Tayyip Erdogan said they have been banned from all government press events in retaliation.

Reporters from newspapers and televisions close to Fethullah Gulen, a former ally of the Turkish president who lives in self-imposed exile in Pennsylvania, said they no longer have access to the presidential palace and have been taken off official mailing lists.

The prime minister's office and key ministries have also become off-limits for correspondents of the Zaman and Bugun newspapers, the Samanyolu TV station and Cihan news agency, they say, adding that the move is a further blow to Turkey's press freedoms.

"This is a war, a fight, an effort to wipe out Hizmet," Tercan Ali Basturk of the Gulen-affiliated Journalists and Writers Foundation, told Reuters, referring to Gulen's movement.

Hizmet (Service) proposes a moderate and modern interpretation of Islam and has extensive influence in the Turkish police and judiciary.

Gulen members are believed to have infiltrated the secret services, law enforcement offices and even the ruling AK Party, prompting Erdogan to claim that the 70-year-old cleric has built a "parallel state" in Turkey.

The president has accused his former ally -- who commands a global empire of media outlets, private schools and charities -- of trying to topple his government through a graft probe that was given ample coverage by Gulen's media.

Government officials defended the press ban saying it targeted biased journalists who served a political agenda.

"The priority of some press institutions is not journalism but serving their political agenda... There are journalists who criticise the government and are still covering it, but the Gulenists had a particular agenda," said an official speaking on condition of anonymity.