The statement comes days after a Tata Sons statement that said Mistry, with the help of independent directors, was trying to take over Indian Hotels Co (>> Indian Hotels Company Ltd), which owns the Taj chain of hotels, when he was heading the $100 billion steel-to-software conglomerate.

Mistry's statement said it was unfortunate to question the independence of the directors given that they were well-known names in the Indian business fraternity.

The independent directors on the Indian Hotels board include Deepak Parekh, chairman of Indian mortgage lender HDFC Ltd (>> Housing Development Finance Corp Ltd) and Nusli Wadia, chairman of the Wadia Group, a textiles-to-aviation conglomerate.

He added that six out of nine independent directors were appointed during his predecessor Ratan Tata's tenure.

In a boardroom battle last month Mistry was ousted as chairman of Tata Sons, with patriarch Ratan Tata back at the helm temporarily. A bitter public spat has since ensued between the two sides. [For a take a look: nL4N1DC44J]

While Tata Sons pins Mistry's removal on his performance, a breach of trust and several other factors, Mistry in an earlier letter blamed Ratan Tata for some of the legacy issues the group faces and highlighted corporate governance failures at some operating companies.

Mistry in the statement on Sunday said the strategy of individual group companies should be created by their own management and approved by their own board of directors.

This would allow the independent directors to ensure the rights of minority shareholders were in sync with that company's business model, Mistry said.

Separately, Tata Sons in a release reiterated that it was "crucially important" for board members including independent directors to consider that their views should ensure that the future of Tata companies and all its stakeholders is protected.

Tata Sons has called shareholder meetings at group companies including Tata Motors (>> Tata Motors Limited), Tata Steel (>> Tata Steel Limited), Indian Hotels, Tata Consultancy Services (>> Tata Consultancy Services Limited) and Tata Chemicals to vote Mistry off those businesses.

(Editing by Jane Merriman and Dale Hudson)

By Aditi Shah and Suvashree Choudhury