People walk under Turkish flags outside an Evet (Yes) campaign tent in the main square on April 11, 2017 in Sivas, Turkey | Chris McGrath/Getty Images Polls predict Yes victory in Turkey’s constitutional referendum At issue is whether to grant President Erdoğan sweeping new powers.

Two Turkish opinion polls show a narrow win for the Yes side in the country's upcoming constitutional referendum, Reuters reported.

Voters will go to the polls Sunday to decide whether to hand sweeping new powers to President Recep Tayyip Erdoğan.

If the referendum were held now, 52 percent of Turkish voters would back the Yes side, according to pollster ANAR, which based its cross-country survey on face-to-face interviews with more than 4,000 Turks. The poll further showed the number of undecided voters has fallen to 8 percent.

A separate survey, conducted by the Konsensus polling company, put the Yes vote to 51.2 percent after the distribution of undecided voters. The poll included 2,000 people in 41 provinces.

The results only apply to voters in Turkey, though voters abroad also skew toward Yes, according to observers. Erdoğan has said that the Turkish diaspora has turned out in greater numbers to vote, which pollsters predict could benefit him.

The constitutional overhaul, proposed by the ruling Justice and Development Party (AKP), would replace Turkey’s parliamentary model of government with a presidential system.