Police in Australia are examining a so-called "war crimes" dossier of information that claims to confirm Sri Lankan forces bombed and shelled civilians during the country's civil war.
And activists have called on the Australian authorities to make use of laws that allow the police to charge people with war crimes for offences committed outside of the country.
Just days ahead of a meeting in Perth of heads of Commonwealth nations, activists claim information gathered from witnesses now living in Australia provides sufficient evidence for the authorities to act against those responsible for what took place two years ago.
Local media has claimed Sri Lanka's former naval chief, Thisara Samarasinghe, who is currently Sri Lanka's High Commissioner to Australia, is named in the dossier. He has denied any wrongdoing either by him or his forces.
"Those responsible for war crimes and crimes against humanity at the end of the Sri Lankan civil war in 2009 must not be allowed to go unpunished," said John Dowd, president of the International Commission of Jurists, Australia (ICJA).
"Under Commonwealth law, there is ample possibility to prosecute these most serious offences here, where Australia has custody of a person and where immunity does not apply."
An independent panel established by UN Secretary General Ban Ki-moon reported earlier this year that there was "credible evidence" that both the Sri Lankan forces and those of the rebel Liberation Tigers of Tamil Eelam (LTTE) had committed war crimes during the final stages of the fighting.
The panel, which said that tens of thousands of civilians may have been killed, called for an independent international inquiry to be held, though none has taken place.
Among the allegations was the "systematic" shelling of a supposed "no-fire zone" where a makeshift clinic was located..
The dossier compiled by the ICJA claims to both "corroborate and substantiate" the claims made by the UN panel and says that more than two years after the conclusion of fighting in Sri Lanka, no-one has been charged or tried over what took place.
Speaking last night from Sydney, Mr Dowd confirmed that his association believed there was sufficient evidence for the Australian police to take action, but refused to be drawn on which individuals ought to be charged.
"We are not commenting on which individuals may or may not be named. We have handed over the information to the police for them to take action," he said.
Sri Lanka has always stridently denied allegations of war crimes or misconduct and says it was engaged against an enemy that had for years used brutal tactics against civilian and military targets alike.
For a long time it denied any civilians had died during the operation against the LTTE, though more recently it has conceded that it "it was impossible" to avoid civilian deaths despite the military's best efforts, given the magnitude of the fighting and ruthlessness of the opponent.
Australian federal police confirmed they were looking at the dossier. They also made clear they have the powers to prosecute individuals for offences such as war crimes, even if committed outside of the country.
The pressure on the Australian authorities to conduct an inquiry comes at a potentially embarrassing time. Next week, Australia is hosting a meeting of 54 leaders of Commonwealth countries, among them Sri Lanka's President Mahinda Rajapaksa.
There are differing reports as to whether Mr Rajapaksa is himself named in the dossier.
Palitha Kohona, a joint citizen of both Sri Lanka and Australia who currently serves as Colombo's representative to the United Nations, is already being investigated by Australian federal police over his alleged role in a surrender deal, first revealed by The Independent, in which several senior civilian members of the LTTE were shot dead.