A decade after two bombs killed scores of tourists at two nightclubs on Indonesia's resort island of Bali, survivors and victims' families have braved a fresh terrorism threat to remember those lost to the tragedy.

Security was tight with more than 2,000 police and military, including snipers, deployed to guard the memorial services.

Reports involving the "certain movement" of terrorists were announced two days earlier, raising the security alert to its highest level.

The 2002 bombing was Asia's deadliest terror attack, killing 202 people, including 88 Australians and seven Americans, and injuring more than 240 others partying at the popular Sari Club and Paddy's Pub in Kuta that night.

The attack was carried out by suicide bombers from the al-Qaeda-linked group Jemaah Islamiyah.

It started a wave of violence that hit an embassy, hotels and restaurants in the country.

"The loss is not just giving us grief, it is also giving us the strength to fight terrorism and all other extremist activities," said Bali Governor Made Mangku Pastika, the former police chief who led the investigations following the attacks.

Australian Prime Minister Julia Gillard attended today's event along with John Howard, who was prime minister at the time of the attacks.

Indonesian Foreign Minister Marty Natalegawa along with other dignitaries also paid their respects.

"On September 11, terrorists attacked the great symbols of American prestige. Here in Bali, they attacked our people and, through them, sought to overwhelm our values," Ms Gillard said.

"Here on these bustling streets, they inflicted searing pain and grief that will never end. But even as the debris fell, it was obvious the attack on our sense of ourselves - as Australians, as human beings - had failed."

Many attending the memorial under sunny skies walked past a row of colour photos covering large black boards.

Others sat in white chairs with their heads bowed as they listened to the speeches encouraging remembrance and healing.

Each victim's name was read and candles were lit in a pool to represent each of the nations that lost citizens from numerous religions.

Memorial services were also held across Australia to mark the anniversary.

In the capital, Canberra, dignitaries and family members of those killed gathered at Parliament House to mourn.