The letter was sent by India's Ambassador to the UN Asoke Mukerji to Ban around December 18-19 along with other documents and information like Khobragade's passport details.
Mukerji told PTI that he wrote the letter to Ban "informing him that we have now a new diplomat who is a Counsellor and we also write that we would like her to have
the same privileges and immunities as a diplomatic officer. We also indicate where her name will be printed in our delegations' list."
The UN had confirmed on Friday that it has received official notification from India to accredit Khobragade, the deputy Consul General at the Indian Consulate here who was arrested on visa fraud charges, to the Indian Permanent Mission and said the request will be processed according to "standard procedures."
Mukerji said the papers are being processed and the UN has to send Khobragade's documents to the US Office of Foreign Missions, which is part of the US State Department protocol for clearance.
Mukerji also met Deputy Secretary-General of the United Nations Jan Eliasson and explained to him the request that India has made regarding Khobragade.
"The UN is fully aware of it. From our side all documents have gone, the State department will have to respond to the UN documents. Now it is between the UN and the US State Department," he said.
"That is where things are right now," he said adding that submission of the papers result in the issuance of an id card.
In Khobragade's case, since she is a diplomat in the rank of a counsellor, "we expect to get a diplomatic id card from the US State Department."
Khobragade was arrested on December 12 and released on USD 250,000 bond after being charged with visa fraud and for submitting false documents to obtain a visa for her domestic help Sangeeta Richard.
She would get UN immunity once she starts working at the UN for whatever she does in the UN.
Mukerji did not comment on how Khobragade's transfer from the Indian Consulate in the city to India's UN mission will impact her case.
"I do not know about other matters as that is not part of my letter," he said, adding that it is now with the State Department to issue Khobragade the UN diplomatic identity card.
Sources have said that the UN has no role in giving immunity to anybody, immunity is given by the US because they have a headquarters agreement, which regulates the privileges, immunities and responsibilities of the all people working in the UN as far the US is concerned.
This agreement was signed when the US offered to host the UN in New York.
A posting at the Indian mission to the UN is expected to accord Khobragade more diplomatic immunity from prosecution in the US but it remains unclear if she would get immunity from the criminal charges, which were levelled against her when she was the Deputy Consul General at the Consulate.