Mori Building Co., Japan's largest closely held developer, is planning projects in central Tokyo worth an estimated ¥1 trillion with its partners, as the city prepares for the Olympic Games in 2020.

Mori is opening Tokyo's second-tallest building next week, and plans to develop about 10 projects over the next decade in Minato ward, President and Chief Executive Officer Shingo Tsuji said at a press conference in Tokyo on Wednesday.

Developers are boosting investments ahead of the Tokyo Olympics in six years, as vacancy rates decline and rents climb.