Rajapaksa used the opportunity of welcoming delegates to the three-day summit to reiterate the message that Sri Lanka has nothing to answer for on human rights, an issue that has cast a cloud over the meet.
Undaunted by a boycott by some leaders and the raging debate on rights violations, Rajapaksa did not directly refer to concerns raised by certain member countries but made a veiled reference to them in his speech.
"If the Commonwealth is to remain relevant, the member countries of the association must respond to the needs of the people and not turn it into a punitive and judgemental body," he said, cautioning against bilateral agendas being introduced against the traditions of the grouping.
External Affairs Minister Salman Khurshid, British Prime Minister David Cameron and other leaders of the 53-member body were present at the opening ceremony.
"Make the Commonwealth a truly unique organisation for engaging in collaborative unity rather than indulging in prescriptive and divisive ways," he said, seeking the strengthening of the grouping.
"We have the greatest regard for human rights and we have restored the right to life. In the past four years there has been no single terrorist incident anywhere in Sri Lanka," he said to thunderous applause from the gathering in the Chinese-built "Nelum Pokuna (Lotus Pond) Rajapaksa Theatre".
Rajapaksa thanked Commonwealth members for reposing confidence in Sri Lanka, saying this would assist him in serving his country that was back on the path of peace and stability after three decades of terrorism.
He quoted Lord Buddha's words to say, "let us only be concerned about what one has done and not what one has not done in the past."
Prime Minister Manmohan Singh decided to skip the conference in the face of strong opposition from political parties in Tamil Nadu, which wanted India to boycott the summit.
Canadian Prime Minister Stephen Harper and his Mauritius counterpart Navin Chandra Ramgoolam boycotted the meet, citing the poor human rights record of the hosts.
While Parliamentary Secretary and MP Deepak Obhrai is representing Canada, Mauritius Foreign Minister Arun Bullel is attending the summit.
After the opening of the summit by Prince Charles, deputizing for his 87-year-old mother Queen Elizabeth II, the head of the Commonwealth, Cameron flew to Jaffna, the headquarters of the Tamil-dominated Northern Province, where people who lost their kin in the war took to the streets to protest against the Rajapaksa government.
Cameron, slated to meet Rajapaksa after his return from Jaffna, is expected to discuss the alleged rights violations against Tamil civilians in the last phase of the war against the LTTE.
Though he refused to join the boycott, Cameron said last week he had some tough questions to ask of the Sri Lankan government.
Rajapaksa on Thursday said that while he would meet Cameron, he too had some questions to ask of him. In all, 23 heads of government and high dignitaries and foreign ministers of the grouping are attending the summit.
In his speech, Rajapaksa asked Commonwealth members to collectively find ways to tackle challenges facing the nations, most of whom are small, developing and lower middle income countries.
He said the Commonwealth had the primary duty of lifting its people above poverty. "That is why we chose the theme of 'Growth With Equity and Inclusive Development'," he said. Governments should prioritise the provision of basic needs like healthcare and safe drinking water and the eradication of poverty and hunger, he added.
Without referring to the war against LTTE, outgoing Commonwealth Chairman and Australian Prime Minister Tony Abbott said Sri Lanka has faced many challenges in the past and has more freedom now.
"We are here to praise as much as we judge. Justice today is better today. Justice tomorrow will be better than today," he said.
Prince Charles, in his speech, said Sri Lanka had faced many challenges, including the 2004 tsunami that devastated the country.
Like Abbott and Prince Charles, Commonwealth Secretary General Kamalesh Sharma spoke of the relevance of the grouping and its charter, and its commitment to values like democracy and freedom.
After a retreat on Saturday, the leaders will meet on Sunday morning to finalise a joint communique that will touch on various issues, including economic development and the developments agenda post-2015.