When asked whether the Government had done enough to explain the reasons for supporting US policy of military action, 83 per cent said that more needs to be done.
The survey also shows there is a lack of clear understanding of the Government's direction on the issue, with 61 per cent of almost 1,000 adults surveyed saying they do not know enough about British policy towards Iraq.
The results echo calls from senior backbench MPs and Trade Union leaders this week that Tony Blair needs to provide better evidence of any danger posed by Saddam Hussein.
The Government is expected to attempt to do just that shortly before the Labour Party Conference later this month, when it is expected to publish its dossier on Iraq.
It is hoped this will have more impact than a document published this week by the think-tank the International Institute of Strategic Studies.
This was criticised in some quarters for not offering any new information and containing too few facts on any potential Iraqi nuclear capability.