Former US secretary of transportation Elaine Chao allegedly used her department's staff to promote her father and Foremost Group founder James Chao, a watchdog report published said.

The bulk of the report, from the Department of Transportation's Office of Inspector General, described Elaine Chao as using department staff to coordinate events where she and her father would appear.

The inspector general also said members of her staff were assigned to edit James Chao's Wikipedia page. And they allegedly worked on a chapter about him and Foremost — currently run by his daughter, Angela Chao — for the book Dynasties of the Sea II and solicited a foreword for his biography, Fearless Against the Wind.

"Throughout 2017 and 2018, more than three [of the secretary's] staffers were involved in editing Dynasties, together with Foremost Group staff," officials said in the report.

"Drafts of Dynasties edited by [the secretary's] staffers focused primarily on the accomplishments of [James Chao], Angela Chao and Foremost Group; the working title of the Dynasties chapter edited by [the secretary's] staffers was 'Dr James Chao & Angela Chao, Turning the Impossible into the Possible.'"

Dynasties of the Sea II was published by Marine Money in 2018.

Elaine Chao's staff were also tasked with working on copy for Journeys — An American Story, which includes an essay from the former secretary about her family's story. That book was also published in 2018.

Members of staff also were said to have developed a media kit for James Chao and worked with Columbia University and SUNY Maritime College to promote events where he was receiving awards.

In total, the report detailed 14 events where Elaine and James Chao were planning to attend and where the Department of Transportation's staff provided support.

The report also described an ultimately aborted 2017 trip to China, that James and Angela Chao were slated to accompany Elaine Chao on and would include the former secretary attending a signing of Fearless Against the Wind.

The report was the result of an investigation requested by members of Congress in September 2019 into Elaine Chao and the potential use of her office to enrich Foremost.

The Congress members cited alleged cutbacks to federal programmes supporting domestic shipping, the China trip and Elaine Chao's alleged appearance in Chinese media interviews alongside her father, and the Department of Transportation seal as reasons for the investigation.

James Chao and his daughter, Angela. Photo: Chao Family Foundations

The resulting report was forwarded to the Department of Justice in December 2020, but both the US Attorney's Office and the Public Integrity Section declined to pursue criminal charges.

Foremost declined to comment.

In a statement from a spokesperson, Elaine Chao argued that the investigation and subsequent report were politically motivated.

"This report exonerates the secretary from baseless accusations and closes the book on an election-year effort to impugn her history-making career as the first Asian-American woman appointed to a president's cabinet and her outstanding record as the longest-tenured Cabinet member since World War II," the spokesperson said.

Elaine Chao had served as transportation secretary after a stint as labour secretary under former US president George W Bush.

She served nearly the entirety of former President Donald Trump's tenure in the White House, stepping down on 7 January 2021 — less than three weeks before President Joe Biden was inaugurated — following the riot at the Capitol building.