Rosa Lee Parks, one of the major figures of the mid-20th Century struggle for African-American civil rights, has died.

She was 92 years old and died in Detroit of natural causes.

Parks gained notoriety when on Dec. 1, 1955, she refused to give up her bus seat to a white man in segregated Montgomery, Ala. By doing so, she violated a city ordinance. She was jailed and fined $14 US.

That act of defiance led to the creation of the Montgomery Improvement Association, led by a young Baptist pastor named Dr. Martin Luther King, Jr.

A boycott of the Montgomery bus system was launched, and lasted 381 days.

The U.S. Supreme Court would eventually strike down the city ordinance, leading to the end of racial segregation on U.S. public transit systems.

Jim Crow laws, in place in the U.S. south since after the civil war reconstruction, had required segregation of the races.

But her act of defiance took its toll on Parks. Having lost her job as a seamstress and facing personal threats, she eventually moved to Detroit in 1957 with her husband Raymond.

Starting in 1965, she began working for Rep. John Conyers, a Democratic congressman. She stayed with him for 23 years before retiring. She remained a champion of human rights.

Parks became a revered figure in her adopted city, with a school and street named after her.

Parks was eventually honoured with the Presidential Medal of Freedom and a Congressional Gold Medal.

A museum and library opened in Montgomery in 2000 commemorating her stand.

Her husband pre-deceased her in 1977.

King would go on to win a Nobel Peace Prize for his work on civil rights. He was assassinated in Memphis, Tenn. in 1968.

Some historical revisionists claim "that my feet were hurting and I didn't know why I refused to stand up when they told me," Parks said in 1992.

"But the real reason of my not standing up was I felt that I had a right to be treated as any other passenger. We had endured that kind of treatment for too long."

In a 1988 interview, Parks fretted that younger African Americans took civil rights for granted.

"(We) have tried to shield young people from what we have suffered. And in so doing, we seem to have a more complacent attitude.

"We must double and redouble our efforts to try to say to our youth, to try to give them an inspiration, an incentive and the will to study our heritage and to know what it means to be black in America today," she said.

Parks and her friend Elaine Eason Steele founded the Rosa and Raymond Parks Institute for Self Development in 1987 to help Detroit's youth develop leadership skills and awareness of the importance of civil rights.

Prime Minister Paul Martin mourned Park' passing in a statement released on Tuesday.

"Rosa Parks was an icon, not just for minority communities in the American south, or for women, but for all of humanity the world over," reads the statement.

"Though Ms. Parks spoke in the quietest of tones, her voice will continue to ring loud as a symbol of courage, of the strength of the human spirit and of the need to continue the fight against inhumanity in all of its manifestations."