The cost to host the 2020 Tokyo Olympics has skyrocketed, with the tally now roughly six times the original estimate of ¥301.3 billion (roughly $2.5 billion) a source said Friday.

Calculations by the Tokyo 2020 Organizing Committee and the Tokyo Metropolitan Government have now tabbed the eventual costs to hit ¥1.8 trillion.

According to one official, the increased estimate is a reflection of soaring costs, including for boosted counterterrorism measures.

"Costs might be significantly reduced if we take measures such as demanding rent reductions," the official said.

Total income from all sources for the games is projected to top ¥400 billion. In the case that costs exceed income, Tokyo will need to shoulder some of the burden making cost-cutting a key issue.