The latest estimate from the trade ministry put the expected cost at some 20 trillion yen ($180bn, £142bn).
The original estimate was for $50bn, which was increased to $100bn three years later.
The nuclear meltdown at Fukushima was triggered by an earthquake and tsunami.
The powerful quake and waves that followed left more than 18,000 people dead, tens of thousands more displaced and well over a million buildings destroyed or damaged.
Almost 4,000 roads, 78 bridges and 29 railways were also affected.
Aftershock
