Texas authorities have offered the incoming Trump administration land on the border with Mexico to build "deportation facilities" in support of the president-elect's plan for the mass removal of undocumented migrants.

Incoming president Donald Trump said this week he planned to declare a national emergency on border security and use the US military to carry out the mass deportation of undocumented migrants after taking office in January.

On Wednesday, the Texas General Land Office announced that commissioner Dawn Buckingham has offered him more than 1,400 acres (570 hectares) of public land on the US southern border "to aid his administration in carrying out their deportation plans".

The plot of land is a ranch along the Rio Grande river -- serving as a border between the United States and Mexico -- in Starr county. It was acquired by the office in late October, the statement from the agency said.

In a letter dated Tuesday, Buckingham said she had authorized a 1.5-mile easement on the ranch to allow "the Texas Border Wall to be built" after the land was acquired.

She added that her office was "fully prepared" to work with US federal agencies to "allow a facility to be built for the processing, detention, and coordination of the largest deportation of violent criminals in the nation's history."

Republican Trump has repeatedly railed against undocumented migrants during the election campaign, blaming them for "poisoning the blood" of the country and highlighting violent crimes perpetrated by members of the migrant community.

Before his first term as president, he had pledged to build a wall along the US-Mexico border, but the project was never completed.

Karoline Leavitt, a spokeswoman for Trump's transition team, said he would "marshal every lever of power to secure the border", according to US broadcaster ABC.

Authorities estimate that about 11 million people are living in the United States illegally -- many fleeing violence or economic troubles in their countries and looking for a better life in America.

Trump's deportation plan is expected to impact around 20 million families. (AFP)