In case of opening a NRE Account or a NRO account the documents required are almost the same.
List of documents required
1) Completed application form signed and attested by your banker/Embassy of
India/public notary or any person known to the bank and must be accompanied with:
(a) Copy of passport, along with photocopies of address proof, expiry date of passport etc.
(b) Copy of Visa. For many countries in the Middle East a work permit may be sufficient, along with a residence card.
e) One passport photograph of each applicant.
f) For mailing address the following proofs maybe acceptable.
1) Photocopy of Valid Passport stating the overseas address
2) Photocopy of Utility Bill
3) Photocopy of Overseas Bank Statement
4) Photocopy of Valid Driving License
5) Photocopy of Government issued ID Card
6) Photocopy of Credit Card bill
In case an individual cannot come to a branch for opening of the account then, all photocopies of the above documents needs to be attested by an Indian Embassy or Notary or by a Banker overseas.