Cambodia has broken ground for a China-funded canal that will link Phnom Penh to the sea.

Local media say more than 10,000 people, including Prime Minister Hun Manet and senior government officials, took part in Monday's ceremony near the capital.

The 180-kilometer Funan Techo Canal will extend to the Gulf of Thailand, opening a new trade route that will give Cambodia cheaper shipping access to domestic and international markets.

Hun Manet called it a historic project that will help develop Cambodia's logistics network and agricultural sector.

A man attending the groundbreaking ceremony said the canal will have many benefits, including boosting the economy, making it faster to transport goods from the river to the sea and helping preserve roads.

But neighboring Vietnam and the US have become increasingly worried about China's presence in Cambodia.

To the west of the canal mouth is Ream Naval Base, where expansion work has been underway with Chinese support. There are suspicions that the base will be used for military purposes -- something Hun Manet denies.

And there are concerns over the canal's environmental impact, especially on the flow of the Mekong River.

The 1.7 billion dollar project is expected to be completed by 2028.