However, the survey by AtlasIntel also showed the centrist mayor of Bucharest, Nicusor Dan, was likely to defeat whichever of two far-right candidates ends up contesting the election in the second and decisive round.
NATO and EU member Romania is due to repeat its two-round presidential election on May 4 and 18 after the top court voided the original vote in December amid accusations of Russian meddling in favour of far-right candidate Calin Georgescu, who had been leading in the polls.
Moscow denied meddling in the vote.
After Georgescu's candidacy for the rerun was blocked by the top court, both George Simion and Anamaria Gavrila, prominent figures on Romania's hard right, stepped forward, with an agreement that one would stand aside if both candidacies were approved.
The Central Electoral Bureau (CEB) has now accepted both candidacies but there is as yet no decision on who will step aside.
Simion, leader of Romania's second-largest party, the Alliance of Uniting Romanians (AUR)and Gavrila, leader of the Young People Party (POT), were supporters of Georgescu and have been stoking up nationalist fervor with their fiery rhetoric.
The AtlasIntel survey, conducted from March 13-15 and published on Monday on the news website hotnews.ro, showed that either Simion or Gavrila would secure most votes in the first round.
Simion would secure 30.4% of the vote in the first round if he was the far-right candidate, while Gavrila would get 30.2% if she ran, according to the survey.
However, Bucharest mayor Dan, running as an independent, would likely win the decisive second round due to his broad appeal across various voter demographics, according to the survey, though many of those canvassed remained undecided.
Romania's hard-right parties generally take a pro-Russian line in foreign policy and oppose providing military aid to neighbouring Ukraine, a stance that would put Bucharest at odds with the European Union and NATO if either Simion or Gavrila became president.
