MILAN Dec 12 (Reuters) - The financial holding indirectly running Rome's two airports has postponed approval of its 2013 budget and of a multibillion-euro investment plan because of uncertainty over tariffs that need to be approved by the government.
Gemina, a holding company that controls Rome airport operator ADR, said in a statement it had put off until January next year approval of its own budget and ADR's 2013-2022 business plan.
The plan foresees 12 billion euros ($15.7 billion) of investments to revamp Rome's main Fiumicino airport by 2044, of which 2.5 billion euros in the next 10 years.
The development plan has been held back by a long-running dispute with the government over tariffs for airport services.
ADR and the Civil Aviation authority came to an agreement in October, but it needs to be ratified by a government decree before the end of the year to become effective, something now looking increasingly in doubt after Prime Minister Mario Monti said he would resign early.
"Failure to approve it ... would lead to an untenable situation of regulatory, operational and financial uncertainty," Gemina said in a statement.
The planned expansion would bring Fiumicino in line with other international airports such as Madrid, London and Singapore, and aid Italy's competitiveness, according to ADR.
The plan calls for two new runways and a near doubling of the airport's area to 2,700 hectares, with a view to handling 55 million passengers by 2020 and 90 million to 100 million in 2044. ($1 = 0.7669 euros) (Reporting By Silvia Aloisi; Editing by Maureen Bavdek)