NHK has learned that construction on only about 10 of the 56 pavilions at the 2025 World Exposition is progressing on schedule.

Participating countries and economies are to bear the costs of building their pavilions at the Expo 2025 Osaka, Kansai.

So far, only South Korea has submitted to Osaka City the documents necessary to start construction.

According to sources, officials of the Japan Association for the 2025 World Expo say only about 10 exhibitors, including the United States and Canada, have either started or finished selecting contractors and taken other steps necessary for starting construction.

The association held a briefing in Osaka City on Monday for construction companies and interior carpentry firms.

With a majority of participants yet to select contractors, the association urged construction companies to actively take part in the projects.

Negotiations with construction companies are apparently proving difficult because of the complex designs of the pavilions and soaring material and labor costs.

The association says it will urge participants to secure larger budgets and to simplify designs to expedite the work.