Liberal Catholics, AIDS activists and health officials yesterday welcomed Pope Benedict’s comments that using condoms may sometimes be justified to stop the spread of the disease.

“It is ... a major step forward toward recognizing that condom use can play a vital role in reducing the future impact of the HIV pandemic,” said Jon O’Brien, head of the U.S. group Catholics for Choice.

The pope spoke out in a new book called “Light of the World: The Pope, the Church, and the Sign of the Times.” In the book, Benedict made clear he did not want to weaken the Church’s fundamental opposition to artificial birth control, a source of grievance to many ordinary Catholics.

But the book’s section on condoms — a long interview with German Catholic journalist Peter Seewald — marked a crack in the once tightly shut door of Church policy.

The pope cites the example of the use of condoms by prostitutes as “a first step toward moralization,” even though condoms are “not really the way to deal with the evil of HIV infection.”

The Church had been saying for decades that condoms are not even part of the solution to fighting AIDS, even though no formal position on this existed in a Vatican document.

The late cardinal John O’Connor of New York famously branded the use of condoms to stop the spread of AIDS as “The Big Lie.”