GOP frontrunner Donald Trump said he would compel Mexico to pay for a border wall by blocking the Mexicans in the US from sending cash back home. According to him, the cutoff in the flow of cash would force the country to make a one-time payment of US$5-10 billion (AU$6.61-13.22 billion) for the wall.

Trump said he would enact new regulations that would require the money transfer companies to verify the client’s identity and legal status before they authorise a wire transfer. The proposition was made on the lines of the post-9/11 USA Patriot Act.

The plan seeks to put pressure on the country by barring undocumented money transfers to the other side of the border through the Mexicans based in the US.

US President Barack Obama said that the proposal was “half-baked” and “impractical. He added that the plan can have unprecedented implications on the Mexican economy.

“(It) actually sends more immigrants north because they can’t find jobs back in Mexico,” the CNN quoted him as saying.

The proposition of building a wall along the US border with Mexico has dominated his campaigns since day one. He said the wall would prevent drug addicts, rapists and criminals from making their way into the US.

“We have the moral high ground here, and all the leverage,” he said in the memo to the Washington Post. “It is time we use it in order to ‘Make America Great Again.'”

Trump also vowed to deport all 11 million undocumented immigrants, the BBC reported. The border wall plan has been widely criticised, with Pope Francis being one of the most prominent figures to do so.

The plan came as Wisconsin went into polls on Tuesday. However, the results were not in his favour. Texas Senator Ted Cruz walked away with the most votes, raising possibilities for a contested Republican convention this summers.