The rule set last year enabled the government to raise tax demands on long concluded deals. British telecoms group Vodafone Group Plc is contesting a more than $2 billion (1 billion pounds) tax dispute over its 2007 acquisition of Indian mobile assets.

India's federal cabinet will take a decision on a conciliation offer from Vodafone, Chidambaram said last week, without giving a time frame.

(Reporting by Manoj Kumar; editing by Malini Menon)