A US government ethics organisation is recommending the White House investigate comments by Kellyanne Conway and "consider taking disciplinary action against her".
The recommendation follows remarks by President Trump's counselor in a TV interview last week.
Ms Conway was commenting on department store Nordstrom's decision to drop a line of Ivanka Trump branded products.
Mr Trump himself said on Twitter that his daughter had been "treated so unfairly" by the retailer.
However, Ms Conway drew extra attention when she told Fox News: "Go buy Ivanka's stuff, is what I would tell you. I hate shopping, I'm going to go get some myself today.
"This is just a wonderful line. I own some of it, I fully - I'm going to give a free commercial here. Go buy it today everybody, you can find it online," she added.
According to Reuters, federal ethics rules in the US restrict executive branch employees from endorsing products in an official capacity. However, the same rules do not apply to the president.
Ms Conway's remarks drew widespread attention, and a bipartisan congressional committee contacted the Office of Government Ethics to query whether or not Ms Conway was in breach of ethics rules.
In a response published online by the OGE, the office's director Walter Shaub writes: "As Ms Conway made these statements, she appeared on screen in a tight frame between the official seal of the White House and the American flag.
"These facts, if true, would establish a clear violation of the prohibition against misuse of position. I note that OGE's regulation on misuse of position offers as an example the hypothetical case of a Presidential appointee appearing in a television commercial to promote a product. Ms Conway's actions track that example almost exactly.
"Therefore, I recommend that the White House investigate Ms Conway's actions and consider taking disciplinary action against her," he added.
He has requested notification of the investigation's findings and any 'disciplinary or other corrective taken' by February 28th.
He noted: "Only in the event that this informal process fails to resolve the matter does the law authorize OGE to recommend disciplinary action."
The White House has previously indicated that Conway had been "counselled" about the remarks.
