They also agreed to finish studies by their governments, industries and experts on the proposed free trade agreement by the end of December so that they could start formal negotiations on the trade pact.
Japanese Prime Minister Yoshihiko Noda told his Chinese and South Korean counterparts at a trilateral summit that it was time to seal the investment treaty as their four-year-long negotiations were getting close to bearing fruit.
"The liberalization of investment rules is one of the big elements for broader free trade pacts," the Japanese Foreign Ministry official told reporters.
"Prime Minister (Noda) stressed the importance of having a fully-fledged investment treaty in order to move forward to the Japan-China-South Korea FTA."
The official declined to give details on the investment treaty as it is still under negotiation. But an investment treaty in general would boost legal stability for investment and help companies to have an enhanced predictability about their business environment.
Noda met Chinese Premier Wen Jiabao and President Lee Myung-bak on the Indonesian resort island of Bali ahead of the East Asian Summit, where boosting economic cooperations in the region is on the agenda.
