India's top renewable energy agency has sent a notice to Anil Ambani-run Reliance Power, asking why it should not initiate criminal proceedings after a subsidiary of the power producer submitted fake documents for a bid, according to a notice dated Wednesday.

Last week, Solar Energy Corporation of India Ltd (SECI) barred the power firm from participating in its clean energy project tenders for three years after it found that a unit of the company had submitted a fake endorsement of a foreign bank guarantee.

SECI said on Wednesday that the bank guarantee submitted by the unit, Reliance NU BESS, was also fake.

"The repeated submission of a fake bank guarantee along with its counterfeit endorsement has been deemed a deliberate act by the bidder, intended to vitiate the tendering process and to secure the project capacity through fraudulent means," SECI said.

Reliance Power said on Thursday it had received a show-cause notice from SECI and added that the company and its unit were the victims of "fraud, forgery and cheating conspiracy."

Last week, the company said that it would legally challenge SECI's ban and had lodged a police complaint against the third party that arranged the bank guarantee.

The notice and ban come as Reliance Power, a coal power generator, is looking to expand into the domestic and overseas renewable energy sector.

Indian companies are increasingly looking to set up clean energy projects as the country targets 500 GW of renewable energy by 2030 as part of its 2070 net-zero goal, up from the current installed capacity of about 154 GW.

In August, Anil Ambani was banned from the securities market for five years and fined about $3 million by the Indian markets regulator on charges of fund diversion.