Donald Trump’s Commerce Secretary Wilbur Ross will retain his stake in a shipping company that sails under foreign flags, the Center for Public Integrity reports.

Mr Ross, a billionaire who made his fortune in the private equity business, had said he would divest millions in assets when he took the Cabinet-level position.

However, he will keep his share of Diamond S Shipping Group Inc, which owns and operates one of the world’s largest fleets of medium-range tanker vessels.

The company is based in Greenwich, Connecticut but incorporated in the Marshall Islands. Their ships transport billions in goods across oceans.

Mr Ross's purview as Commerce Secretary includes all cross-border trade involving the US, litigation matters involving anti-dumping in which China is often the opposing party, US exports promotion, the US Census as well as the National Oceanic Atmospheric Agency.

He will also play a prominent role in Mr Trump’s proposed re-negotiation of the North American Free Trade Agreement.

According to the Center for Public Integrity’s investigation, cited by NBC News, Diamond S Shipping sails under Chinese flags, “ties to a major Chinese investment fund, and one of its ships has travelled to an Iranian port.”

In 2014, Diamond S Shipping filed a document with the Securities and Exchange Commission stating that it will “call on ports located in countries subject to sanctions and embargoes imposed by the US government and countries identified . . . as state sponsors of terrorism, such as Cuba, Iran, Sudan and Syria.”

The Center for Public Integrity’s report also revealed that one of the shipper’s largest customers has part ownership of a Russian state-owned oil company.