Former Turkish president Suleyman Demirel, one of the dominant figures in Turkey's politics for over half a century, has died, reported Anatolia news agency.

He died at 2:05am on Wednesday at Ankara's Guven Hospital of heart failure and a respiratory tract infection, doctors at the hospital said in an announcement broadcast on Turkish television.

He was 90.

Demirel's wife, Nazmiye, died in May 2013. The couple had no children.

He was prime minister several times in the 1960s and 1970s before serving as president from 1993 to 2000. Two of his governments ended in overthrow by military coups.