The APPC today announced that a majority of its management board had on Monday voted to recommend the merger to its members.
The final decision will be taken by the APPC membership at an extraordinary general meeting at a date to be confirmed later this year.
A merger between PRCA and APPC has been informally discussed on several occasions for many years, but the PRCA formalised this earlier this year by taking a proposal to its counterpart.
Details on how the merger might be implemented have not been released.
APPC chair Paul Bristow said: "Following the PRCA's approach to the APPC with a proposition for a merger, the Management Committee undertook a series of meetings with the PRCA to discuss the proposition in depth and to seek reassurances about its impact on both our members and to ensure that our Code of Conduct and Quarterly Register of Public Affairs Practitioners will be unaffected."
Bristow, who was recently re-elected unopposed to a second and likely final term in charge, went on to say: "We will share further details of the merger proposition with our members in due course and we will ensure that all members have the opportunity to ask questions to address any concerns or queries they may have."
Francis Ingham, director-general of the PRCA, said: "A unified representative and regulatory body for public affairs would bring significant benefits to our industry - clarity for politicians and the public; a stronger voice; an even more effective regulatory system. We therefore welcome this recommendation by the APPC Management Committee, and look forward to engaging with the industry in explaining its merits."
Around two-fifths of the nearly 77 firms holding APPC membership are also PRCA members.