The two main candidates running for the office of Istanbul mayor appeared in a televised debate on Sunday night, the first since President Recep Tayyip Erdogan's party came to power in 2002.

The reasons behind the annulment of the first election held on March 31 and how to cope with poverty and unemployment, the two biggest problems facing the largest city of Turkey, dominated the debate between Binali Yildirim, the candidate from the ruling Justice and Development Party (AKP) and a former prime minister, and Ekrem Imamoglu from the main opposition Republican People's Party. 

The AKP suffered a shock defeat in local elections in Istanbul and Ankara after the party and its predecessors had run the two cities since 1994.

Imamoglu beat Yildirim in the March election by a slim margin and served as Istanbul mayor for less than a month before he was disqualified by the Supreme Election Board on May 6.

Turkey's top election body ordered a re-run of the Istanbul election after a challenge by the AKP who claimed there were suspicious votes and irregularities.

Imamoglu said the voting process and the results were crystal clear, while Yildirim repeated his party's claim that the votes cast for him were stolen, without clearly explaining by whom and how. 

Lasting nearly three hours, the debate reportedly drew many audience at homes, coffeehouses and bars as it was broadcast live on major news channels.

Imamoglu hit out at the AKP, saying he could make promises to the voters but since the party had already been in power for 25 years, Yildirim "did not have the right."

Yildirim pointed to his past as transport minister and prime minister, as well as major transportation projects in Istanbul such as the Marmaray underground railway tunnel which has linked the two sides of the Bosphorus since October 2013.

Erdogan earlier on Sunday appeared to play down the significance of the vote for the AKP, pointing to the party's control of 25 out of 39 Istanbul district municipalities. 

"The election in one week is only for mayor," Erdogan said, describing the poll as "only a change in the shop window" and lambasting foreign media's keen interest in the vote. 

(With input from Xinhua, AFP)