The AJ has learned outspoken councillor Peter Phillips and former council member Iain Meek are both putting themselves forward for the top job.
They join Sunand Prasad and Valerie Owen who have already announced their intention to fight concerted presidential campaigns.
Phillips admits his decision has not been made without some reluctance. He said: 'The presidency is not a position I have coveted but in my time as a councillor I have become increasingly concerned at what I believe is the institute's distance from the membership and practicalities of practice.'
Among Phillips' election pledges are a promise to increase the number of council meetings 'to allow more time for council debate on important policy issues' and 'return the ARB to its originally intended purpose of registration.'
Meanwhile Meek has vowed to make the RIBA 'transparently democratic' and 'outreach' to the public as well as governmental and professional bodies.
The final deadline for entering the presidential race is 30 May.