Donald Trump’s family are using his presidency "like the Kardashians used reality TV" to expand their business enterprises, a former White House ethics counsellor has said.

The remarks come after legal documents filed on behalf of Melania Trump revealed she expected to develop “multi-million dollar business relationships” as a result of her presence in the White House. Business documents have also shown she has not stepped away from many of the companies that manage her 'Melania'-branded products since her husband took office.

Ethics watchdogs have said they are worried the First Lady seems to be inappropriately trying to profit from a high-profile position that is usually centred on public service.

“The Trumps are using the White House like the Kardashians used reality TV, to build and vastly expand their overall business enterprises,” said Norman Eisen, who was President Barack Obama's chief ethics counsellor.

A libel lawsuit, re-filed by Ms Trump on Monday in New York, drew particular attention because little has been heard from the First Lady, who last posted on social media on 21 January, for several weeks. She has not been to Washington since the inauguration, and has largely been keeping a low profile in New York.

Ms Trump has been suing the corporation that publishes the Daily Mail's website over a now-retracted report that claimed she once worked as an escort.

While the new court documents do not specifically mention her role as First Lady, an unusual passage argues that in addition to being false and libellous, the Daily Mail report damaged her ability to profit from her high profile, and affected her business opportunities.

Lawyers are using Donald Trump's anti-Muslim rhetoric against him

The passage states that Ms Trump “had the unique, once-in-a-lifetime opportunity, as an extremely famous and well-known person, as well as a former professional model, brand spokesperson and successful businesswoman, to launch a broad-based commercial brand in multiple product categories, each of which could have garnered multi-million dollar business relationships for a multi-year term during which plaintiff is one of the most photographed women in the world".

Charles Harder, Ms Trump's attorney, did not respond to a question about what was meant by the phrase “once-in-a-lifetime opportunity”. He said the first lady “has no intention of using her position for profit and will not do so”.

“It is not a possibility,” Mr Harder said. “Any statements to the contrary are being misinterpreted.”

The products referenced in the lawsuit could have included clothing, accessories, jewellery, cosmetics, hair care and perfume, among others. The first lady is seeking compensatory and punitive damages of at least $150 million (£120 million).

A review of business filings found that Ms Trump has not stepped away from her brand.

As of Tuesday, she was listed in New York filings as the CEO of Melania Marks Accessories Member Corp, the holding company of Melania Marks Accessories LLC, both of which remain active. Those companies managed between $15,000 (£12,000) and $50,000 (£40,000) in royalties from her accessories lines, the Trumps' May 2016 financial disclosure filing shows.

A White House spokeswoman for the first lady did not respond to a request for comment.

In pictures: Women of the world march against Trump Show all 32 1 /32 In pictures: Women of the world march against Trump In pictures: Women of the world march against Trump London An image of President Donald Trump is seen on a placard during the Women's March in London, England Getty In pictures: Women of the world march against Trump Sydney A view of the skywriting word reading 'Trump' as thousands rally in support of equal rights in Sydney, New South Wales EPA In pictures: Women of the world march against Trump Rome People shout and hold signs during a rally against US newly sworn-in President Donald Trump in Rome Getty Images In pictures: Women of the world march against Trump London A protester holds a placard during the Women's March in London, England Getty Images In pictures: Women of the world march against Trump Marseille A placard ready 'Pussy grabs back' is attached to the handle bar of a bike during a 'Women's March' organized by Feminist and human rights groups in solidarity with women marching in Washington and around the world for their rights and against the reactionary politics of the newly sworn-in US President Donald Trump, at the Old Port (Vieux Port) of Marseille, southern France Getty Images In pictures: Women of the world march against Trump Bangkok A young Thai girl holds a "women's rights are human rights" sign at Roadhouse BBQ restaurant where many of the Bangkok Womens March participants gathered in Bangkok, Thailand Getty Images In pictures: Women of the world march against Trump Bangkok A Thai woman takes a photo of a "hate is not great" sign at the women's solidarity gathering in Bangkok, Thailand Getty Images In pictures: Women of the world march against Trump Bangkok American expats and travellers gather with the international community in Bangkok at the Roadhouse BBQ restaurant to stand in solidarity in Bangkok, Thailand Getty Images In pictures: Women of the world march against Trump London Protetesters gather outside The US Embassy in Grosvenor Square ahead of the Women's March in London, England Getty Images In pictures: Women of the world march against Trump Marseille Women's March at the Old Port (Vieux Port) of Marseille, southern France Getty Images In pictures: Women of the world march against Trump Marseille Protestors hold placards reading 'My body my choice, my vote my voice' during a 'Women's March' organized by Feminist and human rights groups in solidarity with women marching in Washington and around the world for their rights and against the reactionary politics of the newly sworn-in US President Donald Trump, at the Old Port (Vieux Port) of Marseille, southern France Getty Images In pictures: Women of the world march against Trump Rome A person holds a sign during a rally against US newly sworn-in President Donald Trump in Rome Getty Images In pictures: Women of the world march against Trump Kolkata Activist Sarah Annay Williamson holds a placard and shouts slogan during the Women's March rally in Kolkata, India AP In pictures: Women of the world march against Trump Kolkata Activists participate in the Women's March rally in Kolkata, India AP In pictures: Women of the world march against Trump London A Women's March placards are rested on a bench outside the US Embassy in Grosvenor Square ahead of the Women's March in London, England Getty Images In pictures: Women of the world march against Trump London A women carries her placard ahead of the Women's March in London, England Getty Images In pictures: Women of the world march against Trump Manila Women protesters shout slogans while displaying placards during a rally in solidarity against the inauguration of President Donald Trump, in suburban Quezon city, northeast of Manila, Philippines AP In pictures: Women of the world march against Trump Berlin Protesters attend a 'Berlin Women's March on Washington' demonstration in front of the Brandenburg Gate in Berlin, Germany AP In pictures: Women of the world march against Trump Berlin Protesters attend a 'Berlin Women's March on Washington' demonstration in front of the Brandenburg Gate in Berlin, Germany AP In pictures: Women of the world march against Trump Berlin Protesters attend a 'Berlin Women's March on Washington' demonstration in front of the Brandenburg Gate in Berlin, Germany AP In pictures: Women of the world march against Trump Melbourne Protesters take part in the Melbourne rally to protest against the Trump Inauguration in Melbourne, Australia Getty Images In pictures: Women of the world march against Trump Macau Protesters take part in the Women's March rally in Macau Getty Images In pictures: Women of the world march against Trump Melbourne Womens march on Melbourne protestors marching during a rally where rights groups marched in solidarity with Americans to speak out against misogyny, bigotry and hatred Rex In pictures: Women of the world march against Trump Macau Protesters hold placards as they take part at the Women's March rally in Macau Getty Images In pictures: Women of the world march against Trump Macau Protesters hold placards as they take part at the Women's March rally in Macau, Macau. The Women's March originated in Washington DC but soon spread to be a global march calling on all concerned citizens to stand up for equality, diversity and inclusion and for women's rights to be recognised around the world as human rights Getty Images In pictures: Women of the world march against Trump Manila A mother carries her son as they join a rally in solidarity against the inauguration of President-elect Donald Trump as the 45th President of the United States in suburban Quezon city northeast of Manila, Philippines AP In pictures: Women of the world march against Trump Sydney An infant is held up at a demonstration against new U.S. President Donald Trump in Sydney, Australia Getty Images In pictures: Women of the world march against Trump Sydney A woman attends a demonstration against new U.S. President Donald Trump in Sydney, Australia Getty Images In pictures: Women of the world march against Trump Sydney A woman expresses her Anti-Trump views in Sydney, Australia Getty Images In pictures: Women of the world march against Trump Sydeney Protesters demonstrate against new U.S. President Donald Trump in Sydney, Australia. The marches in Australia were organised to show solidarity with those marching on Washington DC and around the world in defense of women's rights and human rights Getty In pictures: Women of the world march against Trump London Protesters march from The US Embassy in Grosvenor Square towards Trafalgar Square during the Women's March in London, England Getty In pictures: Women of the world march against Trump London Protesters carrying banners take part in the Women's March on London, as they stand in Trafalgar Square, in central London Reuters

Scott Amey, general counsel of the Washington watchdog Project on Government Oversight, said the First Lady's ongoing enterprises are “another example of the first family blurring the line between public service and private business interests”.

Richard Painter, who advised former President George W Bush on ethics, said the lawsuit's language shows Ms Trump is engaging “in an unprecedented, clear breach of rules about using her government position for private gain”.

Mr Painter and Mr Eisen are part of a group of attorneys suing the president for an alleged violation of a constitutional clause that prohibits presidents from receiving foreign gifts or payments.

President Trump continues to financially benefit from his global business empire, breaking from past practice. Previous presidents and their families have divested from business interests and placed their holdings in a blind trust, although there is no legal requirement to do so.

Mr Trump handed daily management of the real estate, property management and licencing business to his adult sons and a longtime Trump Organisation employee.