Plans have been set in motion to begin work on Donald Trump's most infamous campaign promise.

The Trump administration is seeking almost 18 billion dollars from Congress to complete a border wall between the US and Mexico.

The funds would be distributed over a period of 10 years.

Plans have been made for 316 miles of new barriers and to upgrade an reinforce 407 miles of already existing barriers, according to The Guardian. 

Donald Trump told supporters at a ally during his campaign period that he would be using the border to keep out Mexican illegal immigrants. 

'They’re bringing drugs. They’re bringing crime. They’re rapists,' the US President said at the time. 

He also said the Mexican government would be paying for the wall. 

'I will build a great, great wall on our southern border, and I will have Mexico pay for that wall. Mark my words,' he said previously.

Mexico has continually refused to pay for Trump's wall.