Ministers have launched an investigation into claims that foreign aid officials brushed off allegations of child abuse committed by aid workers.

Priti Patel, who ran the department until November, writes in the Telegraph that the Oxfam prostitution scandal is only “the tip of the iceberg” but that her own officials had “dismissed” her concerns when she raised them.

Oxfam, one of the world’s largest charities, is facing mounting criticism over its handling of sex allegations, but has denied it tried to cover up the use of prostitutes by workers who were supposed to be helping victims of a major earthquake in Haiti in 2011.

The charity’s chief executive Paul Goldring will meet Penny Mordaunt, the international development secretary, on Monday after she threatened to withdraw millions of pounds of government funding. 

He is expected to insist that Oxfam did not inform ministers of the abuse allegations in 2011 because it decided staff accused of paying prostitutes were not guilty of exchanging “sex for aid”.

Ms Mordaunt said the British charity had lied and failed in its “moral leadership” in the wake of the allegations.