Turkish President Erdogan held a rally in Esenler district of Istanbul ahead of Sunday's runoff

President Recep Tayyip Erdogan held a rally in Esenler district of Istanbul on Friday ahead of Sunday's presidential runoff.

"Turkey has come with us to the places that were unimaginable before," he said.

Erdogan, a populist and polarising leader who has ruled Turkey for 20 years, is well positioned to win after falling just short of victory in the first round of balloting on 14 May.

He was the top finisher even as the country reels from sky-high inflation and the effects of a devastating earthquake in February.

Emrah Gurel/Copyright 2023 The AP. All rights reserved
A man walks past a billboard of Turkish CHP party leader and Nation Alliance's presidential candidate Kemal Kilicdaroglu (centre). - Emrah Gurel/Copyright 2023 The AP. All rights reserved

"Our nation has seen the biggest investment and development initiative in our country’s history over the past 21 years," Erdogan told crowds on Friday.

"Our democracy has acquired its strongest position during this period.

"The most successful fight against terrorist organisations has been put up during this period. The influence of our country in the global politics has increased during this period as well."

His challenger, Kemal Kilicdaroglu, the leader of Turkey's pro-secular main opposition party and a six-party alliance, has campaigned on a promise to undo Erdogan's authoritarian tilt.

The 74-year-old former bureaucrat has described the runoff as a referendum on the direction of the strategically located NATO country, which is at the crossroads of Europe and Asia and has a key say over the alliance's expansion.

“This is an existential struggle. Turkey will either be dragged into darkness or light,” Kilicdaroglu said.

“This is more than an election. It has turned into a referendum.”

In a bid to sway nationalist voters ahead of Sunday's runoff, the normally soft-mannered Kilicdaroglu has shifted gears and hardened his stance, vowing to send back millions of refugees if he is elected and rejecting any possibility of peace negotiations with Kurdish militants.

The social democrat had previously said he planned to repatriate Syrians within two years, after establishing economic and safety conditions conducive to their return.

He has also repeatedly called on eight million people who stayed away from the polls in the first round to cast votes in the make-or-break runoff.

Erdogan scored 49.5 per cent of the vote in the first round. Kilicdaroglu received 44.9 per cent.