US national Zhenxing Wang of New Jersey has been arrested and six Chinese nationals and two Taiwan citizens have been indicted for their alleged roles in the scheme, the Justice Department said in a statement.

Wang and his co-conspirators are accused in an indictment of helping North Koreans obtain remote information technology work with US companies that generated more than $5 million in revenue.

The Justice Department said the defendants compromised the identities of more than 80 US individuals to obtain remote IT jobs at more than 100 US companies, including many Fortune 500 firms.

The remote North Korean workers received regular salary payments and in some cases stole sensitive employer information such as export controlled US military technology and virtual currency, it said.

"These schemes target and steal from US companies and are designed to evade sanctions and fund the North Korean regime's illicit programs, including its weapons programs," Assistant Attorney General John Eisenberg said.

US Attorney Leah Foley said the "threat posed by (North Korean) operatives is both real and immediate.

"Thousands of North Korean cyber operatives have been trained and deployed by the regime to blend into the global digital workforce and systematically target US companies," Foley said.

In response to its nationals being named, China's foreign ministry said it would "safeguard the legitimate rights and interests of Chinese citizens".

"China has always opposed unilateral sanctions that have no basis in international law and are not authorised by the UN Security Council," foreign ministry spokeswoman Mao Ning said.