BENGALURU/MUMBAI, Oct. 28 -- Tata Trusts chairman Noel Tata and vice chairmen Venu Srinivasan and Vijay Singh have not approved the re-appointment of Ratan Tata's close confidant, businessman Mehli Mistry, as a permanent trustee-potentially plunging the philanthropic entities that control Tata Sons into turmoil, with the outgoing trustee almost certain to challenge the move in court.

On Tuesday, Noel Tata, TVS Motor Co. chair emeritus Srinivasan, and former defence secretary Singh voted against Mistry's candidature for trustee for life, according to an executive privy to the development.

The three other trustees-former Citibank India CEO Pramit Jhaveri, Mumbai lawyer Darius Khambata, and Pune-based philanthropist Jehangir H.C. Jehangir-...