Two bare-breasted Femen activists staged a protest against Turkey's Prime Minister Recep Tayyip Erdogan on the first day of the country's bitterly-contested local elections.

The two female protesters, who had "Ban Erdogan" written on their chests, were arrested after baring their breasts at a polling station where Erdogan was set to vote, according to reports.

Erdogan had already changed the location of where he was due to cast his vote when the Ukraine-based feminist group said they would stage a protest against him there.

Femen carried out earlier actions in Turkey after Erdogan blocked Twitter last week. In July last year, a topless Femen activist was arrested after taking part in an anti-Erdogan protest at an airport in Istanbul.

Erdogan's Twitter ban was followed a week later by his blocking YouTube on Thursday. This happened one day after a court ordered the suspension of the Twitter ban. Earlier this month, Erdogan said that social media had been abused by his enemies after a stream of audio recordings purportedly revealing corruption in his inner circle emerged online.

The municipal elections have become a crisis referendum on Erdogan and his Islamist-rooted AK Party after weeks of scandal he has cast as a "dirty campaign" of espionage to implicate him in corruption and topple him.

"Today it is what the people say which matters rather than what was said in the city squares," Erdogan told reporters as he voted in Istanbul, his supporters chanting "Turkey is proud of you" outside the polling station. "Once the ballot boxes are opened the rest is only footnotes to history," he said.

Erdogan's AKP Party showed a strong lead in the polls when the first results came in on Sunday evening.