Indonesian presidential candidate and current President Susilo Bambang Yudhoyono shows his ink-stained finger after casting his ballot with his wife, Kristiani Herawati, at a polling station in Cibubur, on the outskirt of Jakarta. (Achmad Ibrahim/Associated Press)

Independent observers declared Thursday that Indonesia's presidential election, which shows a victory for President Susilo Bambang Yudhoyono, was largely free and fair despite accusations of fraud by his opponents.

"So far there is no evidence of systematic or massive fraud," said Nico Harjanto of the Center for Strategic and International Studies.

According to preliminary results released by the National Election Commission, Yudhoyono won with 62 per cent of the vote, based on more than 18.7 million ballots counted. He needed 50 per cent of ballots cast to win in one round.

Former president Sukarnoputri Megawati came in second with 28 per cent, and Vice-President Jusuf Kalla finished third with 10 per cent. An official result is to be released by the commission by July 27.

But Sukarnoputri's campaign alleged that Yudhoyono's Democratic Party committed electoral fraud and threatened to contest the final results.

However, Harjanto said that even if all the contested votes were awarded to Yudhoyono's opponents, the president would still win.

It was unclear if formal challenges to the vote had been filed, but similar complaints from the losers of the 2004 presidential election did not result in formal legal action.

Yudhoyono, a 59-year-old former general who became Indonesia's first directly elected leader in 2004, has been praised for delivering peace to the restive province of Aceh and maintaining economic stability in the face of the global financial crisis.

He has also been credited with cracking down on the Jemaah Islamiyah network, which is blamed for a series of attacks between 2002 and 2005 that killed more than 240 people, most of them foreign tourists on Bali.

Before dictator Suharto was ousted in 1998, Indonesia was under authoritarian rule for three decades.

Observers say Indonesia still faces severe corruption. It is also trying to attract foreign investment to improve its crumbling infrastructure, create an independent judiciary and reduce the poverty of up to 100 million people.

With files from The Associated Press