The party faces losing the London Boroughs Association, the only association it controlled. It could also lose its opposition position on the Association of Metropolitan Authorities. The Liberal Democrats would benefit from both.
The number of Conservative LBA members dropped from 13 to five, with four Liberal Democrat member councils.
As power-sharing agreements are concluded the LBA could become Liberal Democrat controlled, secretary John Hall said.
Last week's local elections also took a heavy toll on senior LBA politicians as well as on its membership. LBA chairman Sir Peter Bowness will be forced to cede his position since the Conservative party lost control in Croydon. His position as opposition chairman of the AMA is also threatened, while his deputy there, Solihull leader Dick Lewis, lost his seat.
Other LBA victims include education and training chairman Paul Clokie, ex-leader of Kingston upon Thames, and Ronnie Barden, environment committee chairman, deposed as Redbridge LBC leader, where no party now has overall control. Simon Randall did not stand for re-election and has retired as chairman of the LBA's housing and social services committee.
The political composition of each association is expected to become clear by the end of June, when each should have held their annual meeting.
Any effects will not be felt by the ADC until June 1995, when its council of members will next be reconstituted.