Former Kenyan prime minister and revered long-time opposition leader Raila Odinga was buried in the west of the country after a service attended by thousands on Sunday.

"Now finally Baba is home," his son, Raila Odinga junior, said beside his father's casket, draped in the Kenyan flag.

The burial concluded days of memorials that at times led to chaos, with at least five mourners dying at other events and dozens injured at a public viewing on Saturday.

Odinga died on Wednesday, aged 80 in an Indian hospital.

He became prime minister after the bloody and disputed 2007 election and was the main opposition leader for many years, losing five presidential campaigns, most recently three years ago.

He retains a devotional following in the west of the country. Former US President Barack Obama, whose Kenyan family hails from the same region, called Odinga a "true champion of democracy".

Politicians, relatives and throngs of his supporters waved Kenyan flags and held his picture aloft as they gathered at Sunday's memorial service, which was held at a university in Bondo.

"Even in the grave, he still remains our hero," one mourner told the AFP news agency.

Military personnel carried Odinga's coffin to the front, where a choir sang and speakers, including Kenyan President William Ruto, remembered him.

"His courage, his vision, and his unyielding faith in our collective destiny will forever illuminate the path of our nation," Ruto said in a post on Facebook about the event.

"His return to Bondo was not merely a homecoming; it was the embrace of a grateful Republic bidding farewell to one of its greatest sons, a patriot who devoted his life to the cause of justice, democracy, and the enduring unity of our beloved Kenya."

Odinga was buried nearby at his late father's homestead, where there is a family mausoleum.

Multiple memorial events had already taken place, including a state funeral in Nairobi on Friday and a public viewing in a stadium in his home city of Kisumu on Saturday.

At the viewing, tens of thousands filed past his open coffin, many crying out the phrase "we are orphans".

At least three people were killed when police opened fire to disperse mourners, with dozens more injured in the chaotic scenes that followed.