Greeks who will head to Sunday's referendum are split over the debt deal the country's creditors proposed, with those in favor of "yes" holding a marginal lead, a survey released Friday showed.

Prime Minister Alexis Tsipras called the referendum last weekend, asking Greeks to decide whether they should accept creditor reform proposals in return for vitally needed bailout funds.

The "yes" camp is ahead with 44.8 percent against 43.4 percent for the "no" camp, according to the results of an opinion poll carried out by polling firm ALCO for Ethnos (Nation) newspaper. About 11.8 percent of the voters are still undecided.

An overwhelming majority, 74 percent of Greeks, said that they want their country to stay in the eurozone, while 15 percent said they preferred Greece to leave the eurozone -- a "Grexit" -- and return to the national currency.

Sixty-one percent of respondents believed that voting "no" increased the Grexit risk, while 30 percent of participants in the survey did not share the view.

Finally, 51 percent of Greeks did not expect that the referendum's outcome will change the lenders' stance if the "no" camp prevails.

Thirty percent of respondents believed that voting "no" could force Greece's interlocutors to shift position in negotiations for a debt deal to avoid bankruptcy and a Grexit for the country, which since Wednesday has been in arrears to the International Monetary Fund.

It has been speculated that if the result of the referendum is "yes", the Greek government is most likely to resign.