MUMBAI (Reuters) - India's Tata Sons in a statement on Thursday strongly rebutted allegations in a leaked letter from ousted chairman Cyrus Mistry to the Tata Sons' board saying the damaging claims in it were 'unsubstantiated' and 'malicious' and went against corporate governance practice.

"It will be beneath the dignity of Tata Sons to engage in a public spat with regard to the several unfounded allegations appearing in his leaked confidential statement," Tata Group said in a press release.

"These allegations are not based on facts or the true state of affairs. It is convenient to put selective information in the public domain to defend one's point of view."

Mistry in his confidential letter to the Tata Sons board soon after being removed from the group had said he was a lame duck chairman and warned of $18 billion writedowns due to poor investments.

(Reporting by Mumbai Newsroom; Editing by Euan Rocha)