The filing, previously expected in September or October, is being delayed because Vodafone wants to wait for new rival Reliance Industries to launch its telecoms services, IFR, a Thomson Reuters publication, cited a source as saying.

A Vodafone Group spokesman declined to comment when contacted by Reuters.

The IPO, expected to raise between 133 billion rupees and 200 billion rupees ($2-$3 billion), could potentially surpass a 155-billion rupees IPO by state-run Coal India in 2010 to become India's biggest IPO.

Vodafone India, the No.2 mobile phone carrier by market share and revenue, and other players in India's crowded telecoms market are bracing for the entry of Reliance Jio, a new telecoms venture controlled by India's richest man Mukesh Ambani.

Reliance Jio, which has already invested $20 billion in buying airwaves and building its network, is expected to launch commercial operations later this year, and will add to the competitive intensity of the market.

Bank of America Merrill Lynch, Kotak and UBS are joint global coordinators and the bookrunners with Axis, Deutsche Bank, HSBC, ICICI Securities and JM Financial for the planned Vodafone IPO, according to IFR.

(Writing by Devidutta Tripathy; Editing by Mark Potter and Alexandra Hudson)