Ioan Mihaila was an advisor to minister Constantin Nita and a member of the supervisory board for the state-owned Hidroelectrica energy firm.
He stands accused of offering backhanders to fellow board member Remus Vulpescu in exchange for his vote on a contract that would have undervalued energy prices and was judged to be "detrimental to the state", prosecutors said.
If the contract had been accepted it would have led to a shortfall of at least 60 million euros for the company, which was declared insolvent last year after losing hundreds of millions in questionable deals signed by its former directors.
During a discussion with Vulpescu and a Hidroelectrica boss, Mihaila said he would keep for himself some of the cash promised by a company that wanted to buy the cut-price energy, prosecutors said.
Another conversation intercepted by prosecutors recorded the head of the energy company, also arrested Thursday, say the energy minister too was aware of the deal.