Obama as unpopular as George W Bush: poll

US President Barack Obama's popularity rating hit a new low with a majority of Americans adjudging him as unpopular as his predecessor George W Bush, a latest opinion poll has said.

"Obama is now as unpopular as Bush. Fifty-one per cent have an unfavourable view of Bush; 51 per cent feel the same way about Obama," said the CNN/ORC International poll.

"Obama's favourable rating is now at 47 per cent - a new low for him, and virtually identical to Bush's 46 per cent favourable rating, a significant improvement over his 2009 numbers," it said.

"This marks the first time in a CNN poll that a majority of Americans have an unfavourable view of Obama," said CNN Polling director Keating Holland.

"And, at 51 per cent, his unfavourable his higher than his favourables for the first time as well," Holland added.

As for Bush, his numbers have gradually edged up over the years since he left the White House, and is now on par with Obama, CNN said.

Both Bush and Obama have much lower favourable ratings than the two men that preceded them in the White House. Sixty-eight per cent of the public has a positive view of former President Bill Clinton and 58 per cent say they have favourable opinion of former President George H W Bush.

The poll also said that the favourable rating of former Secretary of State Hillary Clinton has dropped from 67 per cent in March of 2013 to 59 per cent last fall, 57 per cent in March of this year, and now 55 per cent.

The drop was expected, as Clinton transitioned from America's top diplomat to potential Democratic presidential candidate, it said.

"Secretary of State is often seen as a non-political, non-partisan kind of job, and that showed in Clinton's favourable ratings while she ran the State Department," Holland said.

"In 2011, her favourable rating was as high as 47 per cent among Republicans. Now that she seems to be running for office again, her favourables among Republicans have plummeted to 18 per cent," Holland added.