A Californian fashion label has filed a lawsuit against Ivanka Trump for "exploiting the power and prestige" of her father's position to sell her fashion and lifestyle line.

A class action filed by San Francisco boutique Modern Appealing Clothing (MAC), on behalf of women's clothing brands in California, claims the First Daughter has unfairly profited since Donald Trump became President last November. It claims sales "surged several hundred per cent" off the back of White House promotion and "piggy-backing promotion" at government events.

"President Donald J Trump and his individual and White House employees and agents have, since the elections, promoted defendant Ivanka Trump brand by exploiting the power and prestige of the White House", the lawsuit says. Profits reportedly rose 346 percent between January and February this year compared to the same period in 2016.

Both the President and his senior advisor, Kellyanne Conway were widely criticised for endorsing Ivanka's products on TV and social media following Nordstrom's decision to drop her line.

Conway endorsed her brand from the White House briefing room on live TV — and was later counselled by the ethics committee for doing so.

"I’m going to give a free commercial here", she told Fox & Friends. "Go buy it today, everybody. You can find it online."

While President Trump tweeted his disappointment in the retailer's decision.

Press Secretary, Sean Spicer defended President Trump's tweet at the time saying he had every right to stand up for his daughter.

MAC is seeking damages and a restraining order preventing Ivanka from trading in California.

The First Daughter has faced further accusations of nepotism this week. She accepted German Chancellor Angela Merkel's invitation to a women's economic forum in Berlin next month following a high-level meeting at the White House where she was seated next to Merkel.

Her father's decision to give her an office in the White House and full security clearance even though she is not officially employed by his administration has also raised eyebrows.

Ivanka has handed over the day to day running of her eponymous brand, but still maintains ownership. All assets have reportedly been put in to a trust controlled by her husband, Jared Kushner's family.