Trump attacks Nancy Pelosi over border wall funding

US President Donald Trump has stepped up his attacks on House of Representatives Speaker Nancy Pelosi, saying "she's very bad for our country" and "doesn't mind human trafficking" because she opposes his long-promised wall along the US-Mexico border.

The Republican president also said there is a "good chance" he will follow through on his previous threats to bypass Congress and declare a national emergency to obtain funding for a wall.

Trump, made his comments a week after agreeing to end a 35-day partial government shutdown without getting the $US5.7 billion he had demanded from Congress to help build the wall.

His retreat was seen as a political victory for Pelosi, who became speaker last month when Democrats took over control of the House from the Republicans.

Trump, in an interview, called Pelosi "very rigid" and said she was trying to "win a political point" by opposing his demands to fund the wall.

"I think she's very bad for our country," Trump said when asked what he learned in his negotiations with Pelosi.

"Basically she wants open borders. She doesn't mind human trafficking or she wouldn't do this," he added.

Pelosi has previously backed legislation to fight human trafficking and called it "an abhorrent crime."

A bipartisan House-Senate committee is considering proposals for funding border security measures for the current fiscal year ahead of a deadline in two weeks when stopgap funding ends and a new partial federal shutdown could begin.

Drew Hammill, a spokesman for Pelosi, in a statement, condemned Trump's "wild and predictable misrepresentations about Democrats' commitment to border security."

Trump said at a White House event he might declare an emergency because it did not appear Democrats in Congress were moving toward a deal to provide wall money. Such a step likely would prompt a court challenge from Democrats.

"I think there's a good chance that we'll have to do that," Trump added, referring to the possibility of an emergency declaration.

Construction of a border wall was one of Trump's signature 2016 campaign promises, and he previously said Mexico would pay for it.