Not one of the 423 PROs taking part in the study believed that the Bush administration's PR efforts were credible. Four per cent of those polled said the Iraqi PR campaign was trustworthy.
The survey - conducted among members of global PR bodies including IPRA and the European PR Association - revealed that 36 per cent felt the US Government's PR tactics were not in line with their ethical standards.
PROs from the UK, US and Europe responded to the questionnaire, conducted by German agency komm.passion group over the past three months.
While critical of the US handling of PR on the war, respondents were less sceptical of the UN's comms operations, with 44 per cent saying they believe the information to be balanced and 32 per cent agreeing that UN PR has been credible.
Report co-author Arne Westermann said: 'The credibility loss of the US government is alarming. To repair this "collateral damage" will take as much time as rebuilding Iraq after the war.'
Meanwhile, Washington and Downing Street have launched their 24/7 war PR operation, putting in place a daily briefing system with spokespeople from both governments.