Amid a slump in the Prime Minister Tony Blair's personal ratings, as voters lose trust in him, the IPA has told an inquiry into the Government's communications set-up that it must deliver "holistic and consistent" campaigns in order to maintain people's trust.
The message came in the IPA's submission to a review chaired by Bob Phillis, the chief executive of the Guardian Media Group which this week proposed a shake-up of Downing Street's media operation to curb "spin" after the resignation of Alastair Campbell, the director of communications and strategy.
"There is no doubt that levels of trust in public institutions have fallen over the past few years while at the same time the reverse has happened with many major corporations and brands," the IPA said.
"In this context it is clearly extremely important that government departments ensure the integrity of their communications to the public. They should try, as much as possible, to avoid unclear or contradictory messages, which may be construed as untrustworthy and compound the problem of loss of trust."
The IPA declared it was a "stronger supporter" of COI Communications, which may win a bigger role as a result of the review. A survey of IPA members conducted anonymously last year was "very positive" about COI.
In its report the IPA urged COI to bring in "professional agencies" to a wider range of communications channels and to consider setting up rosters for intranets/extranets, e-mail, mobile text messaging, market research and call centres.
COI's independence was subject to scrutiny a year ago, when BBC1's Panorama questioned its close involvement with promoting Labour policy in the lead-up to a general election.