Sept 1 (Reuters) - Guy Debelle, former Fortescue Future Industries' (FFI) finance chief, has resigned from the board of the iron ore miner's green energy unit to join critical minerals firm Tivan, the Australian Financial Review reported on Friday.

This is the third senior executive departure from Fortescue just this week, exacerbating the company's troubles amid a flurry of top management exits.

Earlier in the week, metals division's CEO Fiona Hick announced departure, and on Thursday the division's finance chief Christine Morris stepped down after only nearly three months into the role.

Tivan in an exchange filing said Debelle, also a former Reserve Bank of Australia deputy governor, will join its board as a non-executive director, but did not mention if he would leave FFI's board.

Fortescue did not immediately respond to a Reuters request for comment.

(Reporting by Sameer Manekar in Bengaluru; Editing by Rashmi Aich)