According to the FIR filed by Ramnarayan Prasad, over two acres of his land was grabbed and a forged registration done in connivance with local officials. Mr Singh, who holds independent charge as the minister of state for micro, small and medium enterprises at the centre, has been named accused no. 25 in the case.
Denying the allegations, Mr Singh, the BJP lawmaker from Nawada, said that he had bought some land in that area but it was from the original land-holder and not from the complainant.
The district magistrate of Patna has ordered a probe by the circle officer of the area. Police have begun investigations but the issue has given the opposition RJD a handle to target the Nitish Kumar-led govt in the state in which the BJP is a partner.
"Will Nitish too ask for Giriraj's resignation, listening to his conscience?" tweeted Tejashwi Yadav, leader of the opposition in the Bihar assembly.
Last year, Mr Kumar resigned as chief minister after Mr Yadav's name cropped up in alleged corruption cases and benami land deals. Mr Yadav, who is the son of RJD chief Lalu Prasad, was then deputy chief minister.
Mr Kumar had also walked out of an alliance that included the RJD and Congress. Later, he formed the government with the BJP.
Mr Yadav also targeted BJP leader and deputy chief minister Sushil Modi who had come up with several allegations of benami land deals involving the RJD chief's family.