The ratings of Democratic presidential candidate Hillary Clinton have dropped, giving opportunities to Republican bets even as their own contest has evolved into an "all-out free-for-all," in the latest ABC News/Washington Post survey.

Compared head-to-head, Clinton does less well than Bush even if he has lost ground in his bid for the Republican Party nomination and settled within reach of other Republican candidates. The gap has closed to three points from 12, to 47-44 in favour of Bush among registered voters from 53-41 two months ago, ABC News reported on Tuesday.

Clinton's favourability among American poll-goers has plummeted to 45 percent from 67 percent, a rating she obtained during her term as a popular Secretary of State. This is the first time her favourability went down since her unsuccessful bid for the presidency in 2008.

Moreover, Clinton faces more trouble in the honesty and trustworthiness department. Here, she is down to 41 percent now from 46 percent two months ago – figures that are well below last year's 53 percent, according to ABC News.

Only 31 percent of voters gave a thumbs-up for the way she handled questions about her use of personal e-mail while she was Secretary of State, while 55 percent disapproved.

On questions about the deadly terror attack on the US consulate in Benghazi, Libya, and on her family's foundation, only 33 percent gave their approval, while 50 percent did not like the way she managed the inquiries.

Clinton held her ground in the empathy category. Forty-nine percent of voters thought she understands their problems, up from 47 percent two months ago before her announcement for candidacy on April 12.

In the Republican field, Jeb Bush posted only 10 percent in favourability from 21 percent in March, losing 11 points in support for nomination among Republicans and GOP-leaning independents who are registered to vote. He has settled alongside Scott Walker and Rand Paul, each with 11 percent, Marco Rubio with 10 percent, Mike Huckabee with 9 percent, and Ted Cruz and Ben Carson with 8 percent each.

Bush, who is expected to announce his candidacy later this month, faces difficulties that include his brother's administration. Only 51 percent think he would create new policies than follow George W. Bush's, compared to the 66 percent who think Clinton will create new policies. The public, by an 18-point margin, gave him a thumbs-down on his answer to the question on whether he would have ordered the invasion of Iraq. Also, 55 percent of voters see him as "out of touch" with the concerns of average Americans.

The ABC News/Washington Post poll was held from May 28 to 31 in English and Spanish via landline and mobile. It was produced by Langer Research Associates of New York for ABC News. Findings have a sampling error margin of 3.5 points for the full sample, and 4 points for registered voters, including design effect. Partisan divisions are 30-22-36 percent, Democrats-Republicans-independents respectively.