Prime Minister Recep Tayyip Erdogan has a central role in Turkey's local elections even though his name won't be on the ballots.

Sunday's elections are widely seen as a referendum on Erdogan's tumultuous rule of more than a decade, and the prime minister has been campaigning as if his own career were on the line.

High profile races for mayor of Istanbul and Ankara with incumbents from Erdogan's Justice or Development Party, better known by its Turkish acronym AKP, will be watched closely for signs of whether his influence is waning.

The Turkish elections board says more than 50 million people are eligible to vote.