I am not sure what you mean by "not contributing". If the offending member is not attending meetings and does not do so for a period of six months he ceases to be a member unless the council votes to accept his reasons for non attendance.
If on the other hand, the member is simply not really 'doing anything', the situation is more difficult and the ultimate call on this belongs to the electorate come election time. In truth, I will venture to say that many councils contain dead wood as it were and many believe that that is preferable to having a needlessly obstructive member.