The Pulitzer prize-winning author Alice Walker has refused to allow an Israeli edition of her classic novel The Color Purple to be published because she believes the country "is guilty of apartheid and persecution of the Palestinian people".

In a letter to Yediot Books, published on the website of the Palestinian Campaign for the Academic and Cultural Boycott of Israel, Walker explained her decision. Although a Hebrew edition of the award-winning novel was published in the 1980s, the author was a juror on a tribunal that met in South Africa last autumn to discuss the Palestine situation. Walker said the testimony she heard was devastating.

"I grew up under American apartheid and this was far worse," she wrote. "Indeed, many South Africans who attended, including Desmond Tutu, felt the Israeli version of these crimes is worse even than what they suffered under the white supremacist regimes that dominated South Africa for so long. It is my hope that the non-violent BDS (Boycott, Divestment, Sanctions) movement, of which I am part, will have enough of an impact on Israeli civilian society to change the situation."

Walker, who took part in the 2011 aid flotilla to Gaza, cited an earlier example of her attempts to "rid humanity of its self-destructive habit of dehumanising whole populations" in her letter: when the film of The Color Purple was completed, she lobbied against it being shown in South Africa.

"It was not a particularly difficult position to hold on my part: I believe deeply in non-violent methods of social change, though they sometimes seem to take forever, but I did regret not being able to share our movie, immediately, with (for instance) Winnie and Nelson Mandela and their children, and also with the widow and children of the brutally murdered, while in police custody, Steven Biko, the visionary journalist and defender of African integrity and freedom," wrote Walker. "We decided to wait. How happy we all were when the apartheid regime was dismantled and Nelson Mandela became the first president of color of South Africa. Only then did we send our beautiful movie! And to this day, when I am in South Africa, I can hold my head high and nothing obstructs the love that flows between me and the people of that country."

The author thanked Yediot Books for its request to publish The Color Purple, the story of a poor black girl in the deep American south between the wars, and said she "would so like knowing my books are read by the people of your country, especially by the young, and by the brave Israeli activists (Jewish and Palestinian) for justice and peace I have had the joy of working beside".

"I am hopeful that one day, maybe soon, this may happen," added Walker. "But now is not the time. We must continue to work on the issue, and to wait." Walker signed off with the hope that "a just future can be fashioned from small acts".