The Donald promised during his election campaign to build a “great wall” to stop “rapists and murderers” getting into the US from Mexico.
He added that he would force Mexico to pay for the construction – which could cost £11 billion.
But Trump’s transition team has allegedly told Republican Party members they plan to use US taxpayers’ money to build the wall – which may also be part fence.
Trump is hoping to use a law passed by former President George Bush which authorised the building of a physical barrier on the Mexican border.
His representatives have reportedly held private meetings to discuss how to use the tax dollars to build the border wall.
This news will come as a big blow to the Trump administration, as making Mexico pay for the great wall was one of the president-elect’s main pledges.
The president-elect previously threatened Mexico with sanctions that would take money away from the country if they did not agree to pay for the wall.
He tweeted: “We will win and establish strong borders, we will build a wall and Mexico will pay. We will be great again.”
Trump has already dropped plans to prosecute rival Hillary Clinton over an email scandal, as promised during his campaign.