Sri Lanka had hoped this week's Commonwealth summit would showcase its post-war revival but the event is turning into PR disaster with the leaders of Canada and India deciding to boycott over human rights concerns.
The Commonwealth Heads of Government Meeting (CHOGM) opens in Colombo on Friday, hoping to tackle a range of economic, social and diplomatic issues affecting the 53-member bloc.
Prince Charles will represent the organisation's ageing titular head, Queen Elizabeth II.
Sri Lankan President Mahinda Rajapakse said he was looking forward to highlighting the island nation's "tremendous transformation" after "suffering for decades from a brutal war against terrorism" that ended in 2009.
But the war's bitter legacy has dominated the build-up, with Indian Prime Minister Manmohan Singh announcing Sunday he would skip the summit after coming under pressure from some of his ministers to send a signal about alleged abuses committed during the conflict.
Canadian Prime Minister Stephen Harper urged his peers in April to follow him in boycotting the meeting to protest Sri Lanka's refusal to probe its troops over allegations 40,000 mainly ethnic Tamil civilians were killed at the end of the separatist war.
British Prime Minister David Cameron has said he will take part, but has pledged to push for an international investigation into the allegations, while New Zealand leader John Key said on Monday his attendance did not imply support for the Sri Lankan government.
Cameron said he would put "serious questions" to Rajapakse, after watching a "chilling documentary" about the events of 2009 that shows footage of alleged war crimes.
Sri Lanka's alleged abuses will almost certainly not be formally discussed during the three-day event given the island's staunch denials of wrongdoing and even as it faces international censure for failing to investigate them.
"The Commonwealth is not a forum to pass judgement on each other's problems," Foreign Minister Gamini Lakshman Peiris told reporters.
"All countries have problems. But those issues must be resolved by the governments of those countries in keeping with the aspirations of their people."
He drew support from Australian Prime Minister Tony Abbott, who on Monday reaffirmed his intention to attend, adding that he did not want Australia to "trash one of the very longstanding and important bodies that we are a senior member of".
But analysts warned the Commonwealth risked sliding into irrelevancy unless countries, including Sri Lanka, directly tackled human rights allegations against fellow members during the biennial meeting.
"The relevancy of an organisation like the Commonwealth depends on its ability to relate to the people who live in those countries, to address issues impacting those people," said Suhas Chakma, director of the New Delhi-based Asian Centre for Human Rights.
"There is no nostalgia left for the British Empire so the Commonwealth cannot rely on this for survival. It cannot afford to shy away from tackling hard issues or it will have no impact at all," he told AFP.
In a bid to modernise, the Commonwealth -- an institution set up 62 years ago with roots in the former British Empire -- developed a series of reforms at its 2011 summit including a charter of common values.
But the bloc brushed aside calls during that summit for an independent commissioner on human rights, democracy and the rule of law, a decision that drew fire from some senior diplomats.
As the summit draws closer, Sri Lanka has also been accused of trying to "shut down" scrutiny of its alleged rights abuses after two politicians, from Australia and New Zealand, were detained in Colombo at the weekend during a fact-finding mission.
Although such controversies are likely to damage the organisation's credibility and reputation, one analyst said the Commonwealth has faced similar episodes in the past and endured.
"The Commonwealth has a long history of weathering the storm on these kinds of issues, from South Africa and apartheid to Zimbabwe and Robert Mugabe," said Mark Rolfe, a lecturer at the School of Social Sciences and International Studies at the University of New South Wales in Sydney.
Rolfe warned the crucial test of CHOGM's survival would be whether Britain's Prince Charles proved an effective head of the Commonwealth when he eventually replaces his mother.
In Sri Lanka, Prince Charles is representing the 87-year-old Queen, who has only missed the summit once, when it was first held in 1971.
"She (the Queen) has provided considerable diplomatic skill to hold the organisation together," Rolfe told AFP.
"He (Prince Charles) has to be capable of providing that some level of diplomacy and goodwill that has been the key to maintaining the Commonwealth."