Japan's Defense Ministry says it will take about 12 years and much more money than initially expected to complete the planned relocation of the US Marine Corps Futenma Air Station.
The Ministry says building a replacement facility in the Henoko District of Nago City may cost about 8.5 billion dollars. That's more than 2.5 times the initial estimate.
In the relocation plan compiled in 2013, Japan and the United States said the Futenma site could be returned to Okinawa as early as fiscal 2022. They also said it would take five years to complete reclamation work.
But Japan's Defense Ministry later found extensive soil improvement work was needed.
The Ministry presented the outline of the revised construction period and cost at a meeting of civil engineering and geology experts on Wednesday.
The new plan says it will take about 12 years to complete the construction of an airfield, including about nine years and three months for soil improvement work and land reclamation.
The relocation is likely to be delayed until at least the 2030s.
The Ministry says it will seek permission from Okinawa Prefecture to alter the construction plan, a request the prefecture is expected to reject. This will likely lead to further delays in the construction work.