The Student Loans Company is contacting some of its customers by telephone amid fears of a fraud attack.
The company says it is calling those customers whom it has "identified as being at risk of having their details compromised".
The student loan system is facing sustained "phishing" attacks, with 1,400 websites shut down this year.
Customers are being told to be "vigilant with their personal details".
The company says it cannot confirm whether or not any private details of customers have been hacked - arguing that it does not want to supply any further information which could be useful to fraudsters.
It also declines to say how many customers are involved as "this is an ongoing enquiry".
But it says the calls to specific customers are being made as a "preventative measure".
The Student Loans Company has four million customers - administering loans to current students and repayments from former students.
But in response to what is believed to be a phishing-style attack - where fraudsters attempt to obtain information such as by email - the company has been directly calling some of its customers.
"We are currently contacting a number of students by telephone who we have identified as being at risk of having their details compromised, to advise them of the necessary security steps they should follow to ensure their details are protected," said Heather Laing, fraud prevention and detection manager for the Student Loans Company.
"We would advise all students to be vigilant with their personal details. Student Finance England or the Student Loans Company will never ask you to verify your personal or bank details by email."
The student loan system has become a target for fraudsters, with the police pursuing extensive phishing operations.
The company has warned of a significant increase in attempted fraud incidents, such as emails dishonestly seeking personal information such as bank details.
The Student Loans Company has also published advice to prevent fraud, telling students and former students to be wary of contacts seeking personal and financial details.
It says that such scams are common at the three main instalment payment dates in September, January and April.