Melania Trump has argued in a defamation lawsuit that a false report by a news outlet impacted her ability to profit from being “one of the most photographed women in the world” as US First Lady.

The lawsuit, filed against the Daily Mail, said the First Lady had a “once-in-a-lifetime opportunity” to garner “multi-million dollar business relationships” while her husband was president.

The newspaper reported incorrect claims the Slovenian model once worked as “elite escort” in the “sex business”. It later retracted the story.

Documents filed in a New York court this week refer to “a multi-year term during which the Plaintiff (Ms Trump) is one of the most photographed women in the world”, when she could “launch a broad-based commercial brand in multiple product categories”.

Those ‘Melania’-branded products would have included apparel, accessories, shoes, jewellery, cosmetics, fragrances and hair care, and skin care products, the lawsuit said.

The First Lady is seeking compensatory and punitive damages of at least $US150 million ($A197 million) for “the commercial harm done to her, her commercial brand and her business opportunities”.

On Wednesday, a spokeswoman for Mrs Trump and her lawyers said she “has no intention” of using her public position for personal gain.

“It is not a possibility,” they said in a joint statement.

“Any statements to the contrary are being misinterpreted.”

But the language in the lawsuit has been considered an admission Mrs Trump views her public role as an opportunity to make money.

Experts say it comes as the Trump administration is already facing accusations of attempting to benefit financially from being in the White House.

“There is concern about Trump and his family profiting materially from their position,” Dr Raymond Orr, a political expert from the University of Melbourne, told The New Daily.

“It’s typically OK for presidents to profit after leaving office, writing a book and making a bunch of money that way, for example.

“But it’s a bit suspect, and people don’t like it, if the White House is used that way [while they’re in office].”

The role of First Lady

Since the 1960s, first ladies have taken “an active if subordinate role in their husbands’ administrations”, said Dr Nicole Hemmer, an expert in Presidential Studies at the University of Virginia’s Miller Center and the US Studies Centre in Sydney.

“Typically they scale back any professional activities during the campaign, then set up an office in the East Wing of the White House after inauguration,” she told The New Daily.

“Melania Trump is quite a deviation from this.

“She only just hired her first staff member (the First Lady usually has about 15 people on staff) and doesn’t currently live in the White House.

“And of course, as her lawsuit suggests, she was looking forward to profiting substantially from the office, something no First Lady has ever said publicly.”

While the President makes $400,000 (around $A520,000), the position of first lady is nonsalaried.

Mrs Trump has previously said she would focus on social causes such as stopping cyberbullying and increasing civility.

Dr Hemmer said first ladies were expected to do voluntary, not paid work, while in office.

“Ethics law means neither the first lady nor president is supposed to talk about post-White House paid work, including memoir-writing, until they are out of office,” she said.

Mrs Trump settled a separate lawsuit this week against an American blogger who published unsubstantiated claims she worked as escort and falsely said she suffered a breakdown.