MEXICO CITY (Reuters) - A report that Mexico s attorney general owns a Ferrari registered at an unoccupied house has added a twist to a growing political battle over who will lead a new institution designed to battle corruption. The report by a Mexican anti-graft group published on Monday said Mexican Attorney General Raul Cervantes had a $218,000 Ferrari registered at an apparently unoccupied house, worth $25,000, in the state of Morelos that also had two other Ferraris and an Audi registered to the same address. Cervantes said through his lawyer he bought a 2011 Ferrari with his earnings as a private lawyer before entering public service, and that it was registered at that address by the company that had imported the luxury car. Cervantes is already at the center of a growing political battle in Mexico, which is implementing a new anti-corruption system that will replace the current attorney general s office with a new institution next year that is designed to be more independent from political interference. President Enrique Pena Nieto s administration has been hit by conflict of interest scandals and his Institutional Revolutionary Party (PRI) has been battered by corruption allegations against several governors. Revelations about the lavish lifestyles of politicians has further damaged the popularity of the ruling class in a country where 44 percent of people are officially poor.  Opposition lawmakers have objected to allowing Cervantes to become the head of the new prosecutor general s office, a figure who will serve a 9-year term in a move away from the current system where the president nominates the attorney general. Ricardo Anaya, the head of the conservative National Action Party, said in a video posted online at the weekend that Cervantes could protect members of the PRI from facing corruption charges if he becomes the new prosecutor general. Anaya has himself been the subject of recent media reports that said his wife s parents had significantly expanded business and real estate holdings in recent years. Anaya has denied any wrongdoing. Cervantes  lawyer said the registration of the Ferrari was an administrative error.   Dr. Cervantes only found out about it this very morning in the newspaper and has already made the corresponding administrative adjustments,  lawyer Cristina Rocha wrote in a letter reposted on Cervantes Twitter page.   In this case, there is nothing illegal, there was only an administrative error in the registry of one address for another in Morelos,  the letter said. Mexicans Against Corruption and Impunity said documents showed 16 luxury cars had been registered to just four homes on the same street of low-cost town houses. The report said neighbors had never seen fancy cars on their street and said the homes in question seemed to be uninhabited. 