BENGALURU, April 12 (Reuters) - Indian telecom operator Vodafone Idea said on Friday it would raise up to 180 billion rupees ($2.16 billion) later this month through a sale of new shares, in what will be the country's biggest follow-on public offering (FPO).

The debt-laden company said in February it would raise up to 200 billion rupees through equity, which included financial support of 20 billion rupees from a top shareholder entity it did not name.

The public offering, which will take place at a floor price of 10 rupees per share, will open for bids from April 18 to April 22, said Vodafone Idea, the country's third-largest telecom carrier by number of subscribers.

Shares of Vodafone Idea were down 2.3% at 12.65 rupees in early trade.

The largest FPO before this was a 150 billion rupee share sale by Yes Bank in 2020.

Vodafone Idea also plans to raise an additional 250 billion rupees through debt for which it has been in talks with lenders, without specifying details.

The company said it would use the equity and debt funding to roll out its 5G network service within six to seven months of securing the funds and expand its 4G coverage.

Larger rivals Bharti Airtel and Reliance Jio have already launched their 5G services in most parts of the country.

Formed in August 2018 as a merger between the Indian arm of UK's Vodafone and Aditya Birla Group's Idea Cellular, the telecom operator has since posted a loss in every quarter since then as subscribers have increasingly switched to rivals.

The company reported total debt of 2.15 trillion rupees, as of Dec. 31, 2023, including deferred spectrum payment obligations it owes to the government.

Its cash and cash equivalents stood at 3.19 billion rupees for the period.

($1 = 83.3150 Indian rupees) (Reporting by Rama Venkat in Bengaluru; Editing by Sonia Cheema)