Archbishop Desmond Tutu on Thursday resigned as Oxfam ambassador, saying he is “deeply disappointed” about the charity’s sex scandal.

The retired church leader said he had taken the decision following allegations of “immorality and possible criminality” by some Oxfam staff in crisis-hit countries.

In a statement, Mr Tutu’s office said: “Archbishop Emeritus Desmond Tutu has supported Oxfam International’s good work for many years, most recently as one of its global ambassadors.

“The Archbishop is deeply disappointed by allegations of immorality and possible criminality involving humanitarian workers linked to the charity.

“He is also saddened by the impact of the allegations on the many thousands of good people who have supported Oxfam’s righteous work.”

Mr Tutu’s office has written to the charity “to inform them of his retirement as a global ambassador”, the statement added.

Oxfam has been engulfed in a sex scandal after it was accused of concealing the findings of an inquiry into claims some of its staff used prostitutes in earthquake-hit Haiti in 2011.

The charity’s former director in Haiti, who has been placed at the centre of the scandal, has reportedly responded by hitting out at “many lies and exaggerations” but admitted he does not “deny everything”.

Roland van Hauwermeiren, who is said to have resigned before the end of Oxfam’s investigation into the Haiti allegations, spoke out in an interview with local media in his native Belgium.