The resignations have implications for PPA subsidiary and customer publishing agency trade body the Association of Publishing Agencies (APA), because under current rules APA members must also pay for PPA membership.
However, Martin MacConnol, the chair of the APA and the CEO of Wardour -- one of those agencies resigning -- downplayed the resignations. He explained that they were in most part the result of a procedural process, which will enable the APA and PPA to resolve a number of unspecified issues.
MacConnol said: "APA and PPA have enjoyed a really strong relationship for more than a decade. Like any relationship, it needs to change and grow. The outcome will be positive for both APA and PPA."
About 75% of the APA's 40 member agencies have decided to not renew their annual membership, which is due for renewal at the end of August.
Customer publishers which have not resigned their PPA membership by August 30 will be liable to pay next year's membership fee. By not renewing their memberships, they are putting the PPA under greater pressure to resolve their concerns.
The 30 agencies represent just above 10% of the PPA's 250-strong member base.
A new PPA-APA relationship will be ratified at the PPA's October board meeting, at which point many of those agencies that have resigned will renew their memberships.
However, Peter Moore, the CEO of PSP Rare, which has clients including Somerfield and Kia on its books, said that his agency would not be renewing its PPA membership regardless of the meeting's outcome.
Moore said: "The PPA has become antiquated and we feel that the services it provides no longer apply in any way to modern publishing."
"The PPA provides no added value to the services already offered by its subsidiary organisation, the APA.
"We're forced to subscribe to both by the PPA terms and conditions, a cost which we believe to be unnecessary."
In a joint statement, the PPA and APA said they are discussing a new corporate and financial relationship to enable the APA to open its membership to a wider group.
The statement said: "The discussions, described by both APA and PPA as 'highly constructive', are taking place between the chairs of the two organisations. A full statement will be issued after the PPA Board meeting in October."
Peter Phippen, PPA's chairman, said: "We are confident that we will agree a new mutually beneficial relationship which will enhance APA and PPA."