Tata Sons, TCS' parent and holding firm for the $100 billion salt-to-software Tata empire, has called for a shareholder meeting at several of its group companies such as Tata Steel and Tata Motors, to remove Mistry from their respective boards.

In a boardroom coup last month Mistry was removed as chairman of Tata Sons and patriach Ratan Tata is back at the helm temporarily. Days later he was sacked as chairman of TCS in which Tata Sons holds more than 73 percent stake.

A public power struggle has since ensued between Mistry and Tata.

(Reporting by Promit Mukherjee. Editing by Jane Merriman)