US President Barack Obama’s popularity has slumped to an all-time low, with a new survey suggesting a majority of Americans for the first time believe him to be dishonest and untrustworthy.

The Quinnipiac University Poll finds Obama’s approval rating nosediving to the level of unpopularity faced by Republican predecessor George W Bush at the same stage of his presidency.

The poll says 54 per cent disapprove of the job Obama is doing, against 39 per cent who approve.

The findings mark a significant downturn from an October 1 survey, which put Obama’s disapproval rating at 49 per cent to 45 per cent approval.

It caps a turbulent few weeks for Obama, whose administration has come under heavy fire for the chaotic roll-out of his signature health care legislation, the Affordable Care Act.

American voters have also reacted strongly against Obama’s misstated pledge to allow voters to keep the healthcare plans they already had, the survey revealed.

“Like all new presidents, President Barack Obama had a honeymoon with American voters, with approval ratings in the high 50s,” said Tim Malloy, assistant director of the Quinnipiac University Polling Institute.

“As the marriage wore on, he kept his job approval scores in the respectable, though not overwhelming 40s. Today for the first time it appears that 40 per cent floor is cracking.”

Malloy said the plunging approval amongst women voters was also a concern for Obama. Only 41 per cent of women approve of the job he is doing, against 51 per cent who disapprove.

The survey indicates that most Americans remain deeply pessimistic about the effect the Affordable Care Act, or “Obamacare” as it has become known, will have on their healthcare choices.

Only 19 per cent of voters expect the quality of care to improve in the next year, 43 per cent expect it to get worse and 33 per cent say it will make no difference.

The poll was conducted amongst 2545 registered voters nationwide between November 6-11, with a margin of error of plus-minus 1.9 percentage points.