The Vatican defended itself on Wednesday against accusations it encourages illegal ivory trafficking, telling elephant lovers it would do what it could to help combat "a serious and unjustifiable phenomenon" but warning campaigners not to expect too much.

The publication of a National Geographic report in September 2012 on illegal ivory pointed the finger at the Vatican, noting the use of ivory in making precious religious tokens and accusing Pope Benedict XVI of accepting or giving ivory items as gifts.

The report sparked a flurry of angry letters and the Vatican responded Wednesday with a long and personal response penned by its spokesman Federico Lombardi to "friends of the elephants".

Lombardi, 70, said he had "never heard or even read a word that would encourage the use of ivory for devotional objects" since he began working at the Vatican and had "never seen a gift in ivory given by the Pope."

Shops within the tiny Vatican state do not sell items made of ivory and nearby stores which flog religious items to tourists are on Italian territory and do not come under the Holy See's jurisdiction, he said.

"The 'Vatican' has no responsibility and no control to exercise over... businesses that are located in the neighbourhood around the Vatican," he added.

The massacre of elephants for their ivory "is a serious problem that Christians can and should unite against, as against all problems concerning the safeguarding of creation," he said.

However, "it is impossible to think that the 'Vatican' might have at its disposal powerful and effective tools for combatting the massacre of elephants by destroying the burgeoning illegal trade in ivory," he added.

Lombardi said the pope intervenes frequently on environmental awareness and assured campaigners that the Vatican would do more to engage Catholics on the issue of illegal ivory trafficking, including launching a series of information programmes on Radio Vatican on the subject.