According to trends from the Election Commission, 45-year-old Nasheed, who had to resign under duress in February last year, led in the initial trends but slowly lost the edge and stabilised at 42.84 per cent of votes.
Under the country's election laws, if none of the candidates get more than 50 per cent of the vote, a run-off will take place between the top two candidates.
A run-off could see Nasheed contesting against Gasim Ibrahim or Abdullah Yameen, who have bagged 24.36 per cent and 27.58 per cent votes respectively.
President Mohamed Waheed was struggling with little over five per cent of the votes.
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The second round of elections is scheduled for September 28 and the new President has to take charge by November 11.
Four candidates - President Waheed, former President and Maldivian Democratic Party candidate Nasheed, Abdulla Yameen, the brother of former President Maumoon Abdul Gayoom and candidate of Progressive Party of Maldives, and Jumhooree Party candidate and business tycoon Gasim Ibrahim - are in the fray for the top job.
According to reports, observers wanted to vote first but people who had lined up at the booths since early morning objected.
Police arrested some persons who were trying to use fake ID cards to vote.
All the candidates expressed satisfaction with the election process.
The wife of President Waheed, who accompanied him to vote, was asked by election staff to join a queue following which she returned without casting her ballot.