Party leader Jairam Ramesh told reporters that Modi has been "doctoring information" on his date of birth and educational qualifications.
He claimed Congress spokesman Shaktisinh Gohil is coming from Gujarat with all the documents and would be addressing a press conference tomorrow on the issue of educational qualifications of the Prime Minister.
On Sunday, Vice-Chancellor of the University M N Patel said that Modi completed his post-graduation in political science from Gujarat University in 1983 and had scored 62.3 per cent as an external student of the varsity.
Congress had yesterday alleged "discrepancies" in Modi's date of birth.
"In students' register of MN College Visnagar (where Modi took admission in pre-science, equivalent to class XII) Narendra Modi's date of birth is mentioned as August 29, 1949. In his election affidavit, he did not reveal his date of birth, but mentioned his age. His official birth date, as available in the public domain, is September 17, 1950," Gohil had said in Ahmedabad.
Gohil had also questioned the timing of Gujarat University sharing details of Modi's Masters degree which it had earlier refused to disclose citing secrecy.