Foreign Minister Vijitha Herath said China's Po Lang, a triple-masted tall ship with 130 crew, was given permission to dock in Colombo because it was "a training vessel and not a research craft".

"There is no change in the policy regarding research vessels," Herath told reporters.

Regional power India is suspicious of China's presence in the Indian Ocean and its influence in Sri Lanka and the Maldives, which are strategically placed halfway along key east-west international shipping routes.

Colombo's navy said the Chinese crew would stay until Friday, visiting "tourist attractions of the country" as well as offering "briefings" to Sri Lanka sailors.

Sri Lanka refused permission for China's Xiang Yang Hong 3 research ship to enter its waters in February, with the craft later moving to the neighbouring Maldives.

Earlier port calls from the Chinese navy since 2022 had raised objections from India.

That included the ship Yuan Wang 5, which specialises in spacecraft tracking, and which New Delhi described as a spy ship.