A charismatic and fiery preacher, Lowery led the Southern Christian Leadership Conference for two decades - restoring the organisation's financial stability and pressuring businesses not to trade with South Africa's apartheid-era regime, before retiring in 1997.

Lowery lived to celebrate a November 2008 milestone that few of his movement colleagues thought they would ever witness - the election of an African American president.

At an emotional victory celebration for President-elect Barack Obama in Atlanta, Lowery said, "America tonight is in the process of being born again."

Lowery also gave the benediction at Obama's inauguration.

In 2009, Obama awarded Lowery the Presidential Medal of Freedom, the nation's highest civilian honour.

In another high-profile moment, Lowery drew a standing ovation at the 2006 funeral of King's widow, Coretta Scott King, when he criticised the war in Iraq, saying, "For war, billions more, but no more for the poor." The comment drew head shakes from then-President George Bush and his father, former president George H.W. Bush, who were seated behind the pulpit.

Lowery's involvement in civil rights grew naturally out of his Christian faith. He often preached that racial discrimination in housing, employment and health care was at odds with fundamental Christian values such as human worth and the brotherhood of man.

Lowery remained active in fighting issues such as war, poverty and racism long after retiring, and survived prostate cancer and throat surgery.

His wife, Evelyn Gibson Lowery, who worked alongside her husband of nearly 70 years, died in 2013.

"I'll miss you, Uncle Joe. You finally made it up to see Aunt Evelyn again," King's daughter, Bernice King, said in a tweet Friday night.

Lowery was pastor of the Warren Street Methodist Church in Mobile, Alabama, in the 1950s when he met King. Lowery's meetings with King, the Rev. Ralph David Abernathy and other civil rights activists led to the SCLC's formation in 1957. The group became a leading force in the civil rights struggle of the 1960s.

He was arrested in 1983 in North Carolina for protesting the dumping of toxic wastes in a predominantly black county and in 1984 in Washington while demonstrating against apartheid.

He recalled a 1979 confrontation in Decatur, Alabama, when he and others were protesting the case of a mentally disabled black man charged with rape. He recalled that bullets whizzed inches above their heads and a group of Klan members confronted them.

"I could hear them go 'whoosh,'" Lowery said. "I'll never forget that. I almost died 24 miles from where I was born."

In the mid-1980s, he led a boycott that persuaded the Winn-Dixie grocery chain to stop selling South African canned fruit and frozen fish when that nation was in the grip of apartheid.

He also continued to urge blacks to exercise their hard-won rights by registering to vote.

"Black people need to understand that the right to vote was not a gift of our political system but came as a result of blood, sweat and tears," he said in 1985.

In a 1998 interview, Lowery said he was optimistic that true racial equality would one day be achieved.

Lowery is survived by his three daughters, Yvonne Kennedy, Karen Lowery and Cheryl Lowery-Osborne. He died at home in Atlanta from natural causes unrelated to the coronavirus outbreak, the family statement said.

Australian Associated Press