Sihanoukville Special Economic Zone says reports that firms in the area were investigated by US Customs for evading duties are false.

A Chinese backed special economic zone in Cambodia has rejected reports that firms operating in the industrial park have been fined by the United States for shipping goods through the Southeast Asian country to evade American tariffs.

The Sihanoukville Special Economic Zone, an industrial park in southern Cambodia funded and jointly run by Chinese investors, said on Thursday night that the 29 businesses in the zone that exported to the US had “not been investigated or punished by US Customs recently”.

“We deeply regret the damage to the reputation of the [zone] caused by the … false reports,” it said in a statement on its website. “We have always insisted on the establishment and the administration of parks according to laws and regulations, and resolutely oppose any illegal activities.”

A representative of the zone declined to comment further.

Emily Zeeberg, spokeswoman for the US embassy in Phnom Penh, said on Friday that the Department of Homeland Security had “investigated and fined a number of companies for evading tariffs in the United States by routing goods through Cambodia”.

“These companies are located in Cambodia’s Sihanoukville Special Economic Zone,” she said in a statement. “Companies sometimes seek to avoid tariffs and pass through products to the United States via transshipment.”

The embassy referred further questions to the Department of Homeland Security, which did not immediately respond to questions sent outside business hours. Reuters first reported the US embassy statement.

More than 160 companies were based in the zone as of April, according to Cambodian Prime Minister Hun Sen, who said the park was a “model of success for Chinese projects”.

The zone is about 12km from Cambodia’s only deep-sea port, which handles around 70 per cent of the country’s imports and exports, and has been touted as a landmark project under Beijing’s Belt and Road Initiative.

The statements come as China and the US remain locked in an tense trade war, imposing tariffs on billions of dollars of each other’s goods.

Analysts said the tariffs had sped up the relocation of supply chains from China to Southeast Asia as companies try to evade the added duties.

Vietnam’s customs department has also reported dozens cases of Chinese goods, including Chinese plywood, being sent to Vietnam to be illegally labelled as “made in Vietnam” before shipping to the US.

This is not the first time the US government has taken action against companies transshipping products from China through Cambodia to avoid duties.

In December 2017, the US Customs and Border Protection agency “took enforcement measures” against Ceka Nutrition for shipping Chinese-origin glycine, a chemical compound used in foods & pharmaceuticals, through Cambodia into the US to avoid an anti-dumping duty order.