Beijing's expansive claims to the South China Sea have long been a source of friction with rival claimants in Southeast Asia, as well as the US which has traditionally been the dominant naval power in the area.

Despite disagreements over Beijing's territorial ambitions, China and Southeast Asia are trying to strike a more conciliatory tone in an effort to stop tensions from spiralling dangerously out of control.

As part of this, the navies of China and the 10-member Association of Southeast Asian Nations (ASEAN) are set to hold their first joint drills, which will take place in the South China Sea.

"As we speak, the navies of ASEAN are en route to Zhanjiang in China for the ASEAN-China Maritime Exercise," Singapore Defence Minister Ng Eng Hen said.

Making the announcement at a gathering of ASEAN defence ministers, also attended by US Defence Secretary Jim Mattis and his Chinese counterpart, Ng said the drills would help to "build trust, confidence".

The city of Zhanjiang in southern China is home to the South Sea Fleet of the People's Liberation Army.

Tabletop exercises between ASEAN and China were held in Singapore in August to prepare for next week's drills.

US officials may however be alarmed that traditional allies in Southeast Asia appear to be drawing closer to China, at a time when concern is already growing in Asia about American commitment to the region under US President Donald Trump.

In an effort to lessen any such fears, Ng also said ASEAN was planning to hold maritime exercises with the US for the first time next year.

Four ASEAN members -- Brunei, Malaysia, the Philippines and Vietnam -- have conflicting claims in the South China Sea with Beijing. China claims sovereignty over almost the entire area, including waters near the shores of smaller countries.

Cambodia, Indonesia, Laos, Myanmar, Singapore and Thailand are ASEAN's other members.

Concerns have escalated dramatically in recent years as China started building artificial islands on reefs in disputed waters, and it has also constructed military facilities and airstrips.

Washington has expressed alarm over the island-building, saying it could affect freedom of navigation in the sea, which hosts some of the world's most vital commercial shipping lanes.