The Institute of Financial Planning and the IFA Association are appealing to members of the LIA and Sofa to "come in and join the party".
They maintain that the door is open for serious discussion with those who are prepared to adhere to the high professional and ethical standards now being set.
IFAA Chairman Bernard Jones says: "The LIA and Sofa have individual qualities and strengths in the same way that the IFP does.
"The alliance is neither elitist nor exclusive. We are not aiming to be confrontational. Everyone is welcome."