White House counsellor Kellyanne Conway looks up during U.S. President Donald Trump's meeting with health insurance company CEOs at the White House in Washington, U.S. February 27, 2017. REUTERS/Kevin Lamarque

WASHINGTON (Reuters) - The head of a U.S. government ethics watchdog said on Thursday he was concerned about the White House decision not to discipline presidential adviser Kellyanne Conway after she publicly endorsed a clothing and jewelry line sold by President Donald Trump’s daughter Ivanka Trump.

“Not taking disciplinary action against a senior official under such circumstances risks undermining the ethics program,” Office of Government Ethics Director Walter Shaub wrote in a letter to White House Deputy Counsel Stefan Passantino.

The ethics office had called for Conway to be disciplined after she said on television last month that people should “go buy Ivanka’s stuff,” in comments that appeared to violate government ethics rules prohibiting the use of public office to endorse products or advance personal business gains.

Passantino had said in a letter to Shaub made public last week that Conway, a senior aide to Donald Trump, had acted “inadvertently.” There was no mention of discipline in the letter.

In a separate letter to the leaders of the House of Representatives oversight panel on Thursday, Shaub said the White House response had made clear that disciplinary action would not be taken against Conway.

“Of greater concern, the White House’s response includes assertions challenging the applicability of ethics rules and OGE’s authority to oversee the ethics program for the entire executive branch. OGE disagrees with these assertions,” Shaub wrote.