Indonesian President Megawati Sukarnoputri broke with tradition when she failed to attend the anniversary of the victory over the 1965 foiled communist coup which led to the rise of former president Suharto.

The ceremony, held at the Lubang Buaya monument in East Jakarta, the site used by the Indonesian Communist Party (PKI) as its base for the abortive October 1 coup, has been presided over by the country's president in every year since 1967, the year Suharto rose to power.

Suharto's successor B.J. Habibie and Megawati's predecessor Abdurrahman Wahid also attended the annual ceremony.

"It appears that she is not attending the ceremony," a spokesman of the president's office, Garibaldi Sujatmiko told AFP.

Sujatmiko said that no reason for the absence had been given but added that the ceremony would be led by the Coordinating Minister for Politics, Social and Security Affairs Susilo Bambang Yudhoyono.

Lubang Buaya (Crocodile Hole) was also where the mutilated bodies of six kidnapped army generals, including chief of staff Achmad Yani, kidnapped, were later found in the shaft of a disused well.

The army, under the command of then Lieutenant General Suharto, crushed the coup later the same day.

The PKI, at the time Asia's second largest communist party after China's, was banned six months later after a bloody crackdown in which up to half a million people died.

October 1 has since been commemorated as the day of victory over the communist threat and is officially known as "Sanctity Day of Pancasila". Pancasila is the five-principle state ideology.