The UK Shareholders' Association said that crucial information was withheld that could have prevented shareholders from losing millions.
According to the newspaper, it could lead to a law suit against the bank and its directors if more shareholders join the cause.
The bank has yet to explain why it did not inform the stock market of a deterioration of its finances in August, the shareholders wanted to know why the announcement was delayed.
Making a statement, the group told the Guardian: "Companies have an obligation to announce significant price-sensitive information as soon as possible and we believe the lack of any such announcements led to a false market in shares of the company."
Northern Rock is set to face the Treasury Select Committee by the end of the month to answer questions regarding the crisis at the bank.