Oriental Land Co., operator of Tokyo Disneyland and Tokyo DisneySea, is planning to spend roughly 300 billion yen ($2.7 billion) to expand the two theme parks, sources with knowledge of the matter said Wednesday.

The company plans to start constructing the new areas -- a 30 percent expansion of the existing parks -- by 2025, one of the sources said.

To free up space, a parking lot adjacent to the parks within the sprawling Tokyo Disney Resort complex in Urayasu just outside of the capital will be turned multistory. The company is also looking to acquire additional land.

Oriental Land has entered negotiations on the new areas with Walt Disney Co., which licenses the rights to properties from Mickey Mouse to Star Wars, with the details to be ironed out by next May.

The investment, the company's largest since pouring 340 billion yen into the 2001 opening of DisneySea, is aimed at attracting older people and visitors from abroad to boost ticket sales that have stagnated amid Japan's falling birthrate and competition from rivals such as Osaka's Universal Studios Japan and other Disney parks in Shanghai and Hong Kong.

The expansion will also serve to ease overcrowding at the parks.

The new areas may carry a Japanese theme to appeal to foreign tourists, a source said.

The company's consolidated sales have seen virtually no growth since fiscal 2013 and visitors to both parks combined in fiscal 2016 fell slightly from the previous year to 30 million.