COLOMBO (AFP) - Outgoing Maldivian President Mohamed Waheed raised concerns on Sunday about the first round of the polls in which he suffered a humiliating defeat, while calling for "peace and harmony" before the final vote.

Mr Waheed received just 5.13 percent of the vote in the first round on September 7, while ex-leader Mohamed Nasheed took the top spot with 45.45 percent.

Mr Nasheed, however, fell short of the majority mark and now faces a tricky run-off against his nearest rival Abdullah Yameen, who garnered 25.35 percent.

"I am very concerned that there are some very serious allegations regarding the election," Mr Waheed said in a statement.

He did not elaborate but said it was "of utmost importance to resolve these issues by the respective constitutional mechanisms, and ascertain justice".

"I appeal to all Maldivian citizens to maintain the same peace and harmony in the second round of voting as well," he added.

The first round passed off without violence and the independent Elections Commission said 88 percent of the electorate turned out to vote in what was only the second presidential election since a new constitution was adopted in 2008.

The commission said the vote was monitored by nearly 4,000 independent observers. There have been no major complaints of fraud or rigging.

Mr Waheed has said he was planning to back 54-year-old Yameen, half-brother of former strongman president Maumoon Abdul Gayoom, in the Sept 28 run-off.

Mr Waheed became the president in February last year after Mr Nasheed, the country's first elected president, resigned claiming a "coup" backed by the military.

Mr Nasheed also accused Mr Waheed of involvement in a conspiracy with former dictator Gayoom to topple his government.

Mr Waheed denies the charges, but the contested change in leadership blemished what was a flourishing democracy in South Asia and has left a legacy of bitterness and distrust.