Addressing a press conference here, HLP chief Maheshwar Singh alleged that Jain was paid higher court fees than other lawyers engaged by the state.
An RTI filed by the party revealed that Jain was paid fees ranging from Rs 55,000 to Rs 1.10 lakh per appearance, he said.
When contacted, Jain dismissed HLP's allegations of undue favour shown to him by the state government as baseless.
He said he was providing services as an advocate to a number of states, including the Himahcal government, agencies and organisations and was being paid as per rules and not a single penny in excess.
Jain said all the payments had been duly accounted in his income tax returns and threatened to initiate legal action agains HLP leaders.