US President Donald Trump will a make a rare primetime television address on immigration as the partial US shutdown over his demands for border wall funding drags into a third week.

It is speculated that the President may use the address to declare a state of emergency. The only problem is it’s yet to be determined what US television networks are actually prepared to screen the live announcement.

As of Monday night, only the CBS television network had confirmed it would air the speech, while ABC, NBC, PBS, and the Fox broadcast network have yet to publicly comment.

Presidents have used Oval Office addresses on broadcast networks to make big announcements for decades, but not all requests for airtime are agreed to by the networks.

CNN reported that where Mr Trump is concerned, factors including his “record of deception” and his tendency to stray off script in long speeches needed to be considered.

Mr Trump announced his intentions in a Twitter post on Tuesday, saying he will discuss the “humanitarian and national security crisis” on the border, but critics have flooded social media calling on the networks to shun the speech.

I am pleased to inform you that I will Address the Nation on the Humanitarian and National Security crisis on our Southern Border. Tuesday night at 9:00 P.M. Eastern.

— Donald J. Trump (@realDonaldTrump) January 7, 2019

Mr Trump’s live address from the Oval Office will take place shortly before a planned visit to the US-Mexico border this week.

The moves indicate the Republican president has no intention of backing off his pledge to build a border wall that he believes will stem illegal immigration and drug trafficking.

Democrats in Congress say a wall would be expensive, inefficient and immoral.

However, pressure to reach a deal is likely to grow as the effects of the shutdown are felt, including possible cuts in food stamp programs and delayed tax refunds.

Mr Trump planned to visit the US-Mexico border on Thursday, White House spokeswoman Sarah Sanders announced on Twitter.

The visit likely will highlight security concerns pushed by the administration as justification for the wall.

Large chunks of the federal government shut down on December 22 over Mr Trump’s demand that a bill to keep the federal government operational include more than $US5 billion ($7 billion) to pay for a wall along the border with Mexico.

About 800,000 government workers have been either furloughed or working without pay since December 22.

Vice President Mike Pence said White House lawyers were evaluating the possibility that Mr Trump could declare a national emergency in order to secure alternate funding for the wall, but that Mr Trump had not made a decision on using that tactic.

Mr Trump has directed the White House budget office to take steps to mitigate the effects of the shutdown, including ensuring tax refunds are delivered, Mr Pence told reporters.

He said Mr Trump also invited Democrats back to the White House to respond to its latest proposal to resolve the stand-off over legislation to fund the government.

Mr Trump last week told lawmakers the shutdown could last months.

Mr Trump has argued the wall is necessary for national security and has tried to link terrorism to illegal immigration, without providing evidence, as justification for the plan.

Democrats say there has been no evidence of suspected terrorists coming through the southern border and that Mr Trump has no grounds to declare a national emergency over the issue.

Democrats, who have taken control of the US House of Representatives, say other border security measures are more efficient and cost-effective than a wall, which is contrary to American values.

-with AAP