David Cameron was pressing for progress on a range of human rights issues as he embarked on a second day of summit meetings with fellow Commonwealth leaders amid continued disputes over key issues.
Piracy, forced marriage, calls for the 54-member body to appoint a rights commissioner and pressure on Sri Lanka to properly investigate war crimes trials were among items on his agenda.
Mr Cameron, attending his first Commonwealth Heads of Government Meeting (CHOGM) since entering Downing Street, warned it must work harder to uphold basic values if it is to remain relevant.
Leaders will spend most of the day locked in discussion at a retreat in Perth, Australia's Kings Park as they seek agreement on proposals to ensure the organisation has a 21st-century role.
Mr Cameron said on Friday that he expected "good progress" to be made - including on developing a "charter" of rights and freedoms.
That was one of 100-plus recommendations put forward by an Eminent Persons Groups - including former UK foreign secretary Sir Malcolm Rifkind - which examined the challenges facing the Commonwealth.
Others which are proving more problematic are the appointment of a independent commissioner for the rule of law and human rights and a call for all member states to repeal laws banning homosexuality.
"I think there is very strong support for the key elements of the Eminent Persons Group," he said. "The Commonwealth is a great organisation, a third of the world's population, 54 countries across six continents, a really great network, but it is a network that must have strong values.
"The Eminent Persons Group report will strengthen those values particularly by having a charter setting out the rights, the freedoms, the democracy that we all believe in, and I think that is important.
"I think we are going to make good progress here in Perth."