The project is leaving Thailand worried about its potential impact on water resource management.

"The Cambodian people – along with people in neighboring countries and the broader region – would benefit from transparency on any major undertaking with potential implications for regional water management, agricultural sustainability, and security," Wesley Holzer, a U.S. embassy spokesperson in Phnom Penh, told VOA Khmer in an email on Tuesday.

The canal project has even left Vietnam, another neighbouring nation, worried over how it would affect its use of water downstream.

Cambodia approved the 180-kilometer-long (111.8 miles) Funan Techo Canal in May, reported VOA.

The project is a part of China's Belt and Road Initiative.

It is the latest Beijing-funded project in the country.

It would connect the coastal province of Kep with Kandal and Takeo provinces inland.

Phan Rim, spokesperson of Cambodia’s Ministry of Public Works and Transport, told VOA Khmer on Tuesday that the project is expected to be built by the end of this year as planned.

The U.S. is urging Cambodian authorities "to coordinate closely with the Mekong River Commission [MRC] to provide additional project details and to participate fully in any appropriate environmental impact studies to help the MRC and member countries fully understand, assess, and prepare for any possible impacts of the project," according to the embassy spokesperson as quoted by the news portal.

Brian Eyler, senior fellow and director of the Southeast Asia Program at the Stimson Center in Washington, said the canal connects with tributaries of the Mekong River, "but indeed the specifications submitted by the Cambodian National Mekong Committee to the Mekong River Commission show the first and shorter section of the canal connecting to the Mekong River in Kandal Province near the Kandal container port."

"If the canal is indeed used for irrigation, then Vietnam's concerns will intensify because the only way to provide irrigation from the canal is to take much more water out of the Mekong than what is specified in the notification document to the MRC," he wrote in an email to VOA.

"So much remains unclear about this project and it seems to be moving forward at breakneck speed with zero room for appropriate levels of information dissemination and regional discourse," Eyler said.