WASHINGTON (AFP) - Donald Trump has historically low approval ratings, but would still have voters' support in a row with Congress, polls suggested Wednesday (Feb 22).

Fresh surveys showed Trump's popularity is languishing - threatening to sap his political capital just weeks into a four-year term.

A Quinnipiac University poll reported 38 per cent of voters think Trump is doing a good job. Fifty-five per cent believe he is doing a bad job.

That is unparalleled for a modern president so early in his term.

Perhaps worse for the White House, 63 per cent of voters said Trump is not level-headed and 55 per cent said he is not honest.

For any normal politician, those numbers would be disastrous - emboldening political rivals and encouraging allies to keep their distance.

Many in Washington are already looking towards Congressional elections in 2018, which present a challenge for incumbent Republicans.

Mid-term elections often serve as a referendum on the president and Democrats are baying to retake 24 seats and control of the House of Representatives, which would put a serious check on Trump's agenda.

Against that backdrop, Republicans may be stuck between an unpopular president and public opprobrium.

Congressional Republicans privately fret that opposing Trump could invite angry tweets, a grassroots firestorm and perhaps even a Trumpite challenger in the next party primary.

They may have reason to worry. A Pew Research poll released Wednesday showed rank-and-file Republicans are still likely to back Trump in an argument with party lawmakers.

"About half of Republicans and Republican-leaning independents (52 per cent) say that if Trump and Republican congressional leaders disagree on an issue, they would be more likely to trust Trump," Pew said.

"About a third (34 per cent) say they would trust GOP leaders if they have a disagreement with the president."