This is a plugin made long time ago taken from Rothgar if I remeber. The thing is I had problem with his plugin(language was not from client game and some bug when you was move in spec like you could block player or see the yours weapons flying). I share it cause some friends of mine use it without problems.
II - Cvars
drapi_afk_manager_move_min - Minimum player to move player
drapi_afk_manager_kick_min - Minimum player to kick player
drapi_afk_manager_move_time - Time to move player
drapi_afk_manager_kick_time - Time to kick player
drapi_afk_manager_warn_time - Time to show warining message
drapi_afk_manager_immune - AFK admins immunity: 0 = DISABLED, 1 = COMPLETE, 2 = KICK, 3 = MOVE
drapi_afk_manager_immune_flag - Admin flag for immunity, blank=any flag
drapi_afk_manager_V1.0.1.zip