US First Lady Melania Trump has been criticised for the choice of her coat worn on a trip to a migrant child detention centre in Texas.

Melania Trump was spotted in the coat, which featured graffiti writing on the back with the words "I really don't care do u?", as she boarded a plane, BBC reported on Thursday.

Her spokeswoman said "there was no hidden message" in the former fashion model's sartorial choice.

The $39 jacket from Zara has caused an uproar on social media.

US President Donald Trump later tweeted that his wife's coat "refers to the Fake News Media".

Twitter users were quick to criticise the first lady's jacket faux pas and the not-so-hidden message.

One user made the point the jacket would likely have been received far better online, had it been worn on any other occasion.

Hours after the photo of her departure outfit went viral, she again donned the jacket to disembark the plane at an Air Force base outside Washington.

She ignored question from reporters as she entered the presidential motorcade.

Melania Trump's spokeswoman Stephanie Grisham lambasted US media on Twitter for focusing on her fashion choice.

Trump was not seen wearing the coat when she first arrived in Texas, but had it on again when she returned to Washington.