The Defense Ministry announced that its estimate of the overall cost of constructing a replacement facility for a U.S. military base in Okinawa Prefecture will nearly triple to 930 billion yen ($8.48 billion) and take much longer than expected.

The government blamed the delay and cost overrun for the reclamation work in coastal Henoko in Nago on the need to solidify a vast expanse of soft seabed at the site.

Details of a new estimate for the project, all funded by Japanese taxpayers, were presented Dec. 25 when specialists met to advise on the reinforcement work for the Defense Ministry.

The facility will replace the U.S. Marine Corps Air Station Futenma in Ginowan city.

The new cost projection is about 2.7 times higher than the central government’s initial estimate five years earlier. It was the first time that the overall cost, including the strengthening work, has been presented to the public by the central government.