British charity Oxfam is investigating ''financial irregularities'' in its flood relief programme in Pakistan.
An independent external audit by PricewaterhouseCoopers is under way after the problem was discovered in the southern province of Sindh.
Oxfam said every effort would be made to recover any missing money.
The charity supplies aid to at least 1.95 million people in Khyber Pakhtunkhwa, Punjab and Sindh. It has provided clean water, sanitation and temporary shelter kits.
More than 1750 people are thought to have been killed by the floods which began in July 2010.
The BBC reports that between 14 million and 20 million people were affected.
The floods started in the north and surged south, destroying 1.2 million homes and damaging about 14% of land under cultivation.