In that capacity, he oversaw investigations of wrongdoings related to the United Nations in a range of countries including within the headquarters.
Nair was appointed to a five-year term as United Nations Under-Secretary-General for Internal Oversight Services on 24 April 2000, succeeding Karl Paschke in that position.
Benon Sevan, the head of the programme, along with UN Deputy Secretary-General Louise Frechette, rejected any such investigation, claiming that it would be too expensive to be worthwhile.
[1] In 2004, Nair was investigated for unspecified internal accusations of graft and sexual harassment against female staff.
Nair relinquished his post upon expiration of his five-year contract and returned to his native Singapore on 23 April 2005.