At a state memorial service for Dr Williams at the national auditorium in Rarotonga on Saturday morning, current prime minister Henry Puna paid tribute.
"Papa Joe had a remarkable career of many highlights, but it was the essence of a man who cared and wanted to serve people that puts him in the good company of our national heroes," he said.
"It was this essence of caring that was to ultimately cost him his life."
Puna said Williams had touched the lives of many people.
"That one of our own sons could have impacted and touched the lives of so many is simply outstanding.
"How proud we all are to have had him among us as a Cook Islander, to have had him as a doctor, to lead us as a politician, and to serve our community as a mentor of knowledge and ideas," Puna said.
