A landmark shift in the Catholic church's hardline position on the use of condoms is in the offing following reports Pope Benedict XVI has said in a new book that their use can be justified in some cases, such as for male prostitutes seeking to prevent the spread of HIV.

The pontiff makes the comments in a book-length interview with a German journalist, "Light of the World: The Pope, the Church and the Signs of the Times," which is due to be published on Tuesday.

Church teaching has long opposed condoms on the basis that they are a form of artificial contraception, while the Vatican has been harshly criticised for its position given the AIDS crisis.

Benedict says in the book that, for male prostitutes for whom contraception isn't a central issue, condoms are not a moral solution.

However, in comments that are likely to be be pored over in the coming days by Catholics around the world, as well as others, he also says that condoms could be justified "in the intention of reducing the risk of infection."

Benedict previously drew unprecedented criticism from European governments, international organisations and scientists in March 2009 when he told reporters while flying to Africa that condoms would not resolve the AIDS problem there but, on the contrary, increase it.

That statement was condemned by France, Germany and the UN agency charged with fighting AIDS as irresponsible and dangerous.

While opposition to condoms is a long-standing church position, the Vatican felt constrained to step in and say Benedict wanted to stress that a reliance on condoms distracted from the need for proper education in sexual conduct.

Austin Ivereigh, a British Catholic commentator and campaigner who is publicising the book in the UK for its publishers, the Catholic Truth Society, said: "The Pope is not actually saying anything that would surprise moral theologians. What is surprising is that it is coming from the Pope."

He added: "The church's teaching on contraception predates AIDS and predates new kinds of moral possibilities, which is that condoms can be used not as a means of preventing a conception but as a means of preventing transmission of a virus.

"Rome has been silent on this for some years. The difficulty has been how they can clarify this teaching without it looking like they are lifting the ban on contraception.

"It may well be that the pope has decided that this is the best way of doing it - through a book-length interview."

Benedict addresses a range of issues in the book, including clerical sex abuse and science and says that if a pope is no longer physically, psychologically or spiritually capable of doing his job, then he has the "right and, under some circumstances, also an obligation to resign."

• This article was amended on 22 November 2010. The words 'no longer' had been omitted from the final paragraph. This has been corrected.