WASHINGTON (AFP) - The outgoing head of the US Government Ethics Office called Sunday (July 9) for more rigorous rules on conflicts of interest, saying the Trump administration had consistently thwarted his agency's work.

Walter Shaub, director of the ethics office since 2013, submitted his resignation last week after months of clashing with White House officials on issues including President Donald Trump's refusal to fully divest his vast business network.

Shaub's criticism, including in tweets that mimicked the president's Twitter style, had drawn unaccustomed attention to the often overlooked ethics agency.

On Sunday, Shaub told ABC that while he had long thought existing ethics rules "were strong enough to protect the integrity of the government's operations, my recent experiences have convinced me they need strengthening."

The tensions between Shaub and the Trump White House have long been evident.

Shaub called repeatedly for Trump to divest his holdings; instead, the new president placed them in a trust managed by two of his sons, with Trump as sole beneficiary.

Every president since the 1970s had moved his assets into a blind trust run by third parties.

In a statement to ABC, the White House accused Shaub of having been "outspoken by leaking, tweeting and writing letters to Democrat" lawmakers without engaging appropriately with White House officials.

Shaub denied that.

He said that "every White House in both Democratic and Republican administrations has been incredibly supportive of the ethics programme, until now." Without such support, he said, he had no alternative but to take his concerns to the public.

He said his agency needed greater authority "to compel the release of documents and records," adding, "I'd like to see some enforcement capacity."

Every president since a 1978 ethics law was passed following the Watergate scandal had "understood that a president can have conflicts of interest and should address them," Shaub said.

"The breach of that ethical tradition has been the start of every problem that's flowed from that in the past several months," he said.

Shaub plans to continue working on ethics issues at his next job, with the non-partisan Campaign Legal Center in Washington.