Jakarta – The Golkar party has endorsed President Megawati Sukarnoputri in next month's run-off election, providing a much-needed boost to her struggling campaign.

She finished second behind Mr Susilo Bambang Yudhoyono in the July 5 presidential poll and continues to trail her former security minister in opinion polls.

But since neither won 50 per cent of the vote, they will contest a September 20 run-off. Golkar chairman Akbar Tandjung announced the endorsement following an all-day meeting of its executive board yesterday.

Before the widely expected announcement, senior Golkar leader Rully Chairul Azwar had said: "This will give us a strong coalition that ensures a stable parliament and empowers all government institutions in the future."

Some analysts said a Golkar endorsement could be the key to Ms Megawati's victory, as the party commands the most seats in Parliament and has a strong political machine that can bring millions of voters to the poll.

Others say the endorsement from the party's top executives may make little difference. In a recent poll, nearly 86 per cent of Golkar supporters said they would vote for Mr Bambang, compared to 9 per cent for Ms Megawati.

Golkar's support for Ms Megawati is linked to its desire to wield significant influence in the next government, some analysts said.

While Mr Bambang has rebuffed Golkar demands for ministerial posts if he becomes president, Ms Megawati's Indonesian Democratic Party of Struggle has reportedly promised it eight of the more than 30 ministerial posts.

"It's a bad strategy and won't work," said Mr Mohammad Qodari of the Indonesian Survey Institute. "I wonder why they still think like this even after the first round of the presidential election."

The endorsement could also complicate efforts by Ms Megawati to paint herself as a reformist candidate and a fighter for the poor. Golkar served as former president Suharto's political machine during his 32-year reign and is still associated with the abuses and corruption of that era.

Mr Bambang, from the small Democratic Party, is the favourite. His popularity has soared, partly on perceptions that he is a clean politician and a strong leader. The retired general has capitalised on voter anger over the President's aloof leadership and her failure to eradicate poverty, curb graft and improve the economy.