Japan's weakening yen and accompanying rising prices are affecting plans for the 2025 World Expo due to be held in Osaka. And that's caused the latest estimate for the cost of the event to surge past the original plans.

The 2025 Osaka Kansai Expo will take place on Yumeshima, an artificial island in Osaka Bay.

Representatives from countries and regions taking part in a conference on the expo visited the island on Wednesday.

Preparations at the site started this month. The construction of the Osaka Pavilion is expected to start around next spring.

Other planned facilities include the "Grand Roof," which will be one of the world's largest wooden structures. However, rising material costs and other factors are having an impact.

The pavilion, which will be set up by Osaka Prefecture and other parties, is expected to cost about 1.5 times the previous estimate.

Osaka Governor Yoshimura Hirofumi said, "We're sorry to residents for the burden of these rising costs. But we will build a great pavilion by improving our cost management."

The venue's construction costs will be shared equally by the central government, local governments and the business community.

A design change and other factors about two years ago pushed expected costs up by about 60 billion yen to 185 billion yen.

But at that time, the yen was around 103 to 105 to the US dollar. The Japanese currency is now much weaker, and recently fell to the 150-yen level.

That puts the estimate at the current equivalent of some 1.2 billion dollars.