KUNMING - China has completed construction on a long tunnel that will allow a major railway to reach countries belonging to the Association of Southeast Asian Nations (ASEAN).

The 10-km-long tunnel, located in Southwest China's Yunnan province, was completed on Tuesday after six years of work by nearly 1,000 construction workers.

The Xiushan tunnel will be pivotal for the construction of the 141-km Yuxi-Mengzi Railway, which is part of the eastern section of the planned Pan-Asia international railway project.

The tunnel is listed as a first-level high-risk tunnel due to complicated geological conditions in the region.

The railway is being built with a total investment of 4.5 billion yuan ($703 million).

The railway is expected to become operational later this year and will boost land transportation between China and ASEAN countries.