We made it clear in discussions in November that we have legal reservations about the deal, Dieter Posch told reporters on Monday.
The ministry said concessions offered by Deutsche Boerse had not addressed its concerns. The ministry, based in Wiesbaden, Germany, has the power to revoke Deutsche Boerse's operating license, a key prerequisite to a successful deal.
The Hessian ministry will give its final verdict on the takeover after antitrust authorities in Brussels have ruled on the deal. A ruling from the European Commission was expected this week. The deal has met intense scrutiny from the European Union.
(Reporting By Andreas Kroner; Writing by Edward Taylor; Editing by Dan Lalor)