"You can’t gloss over this result. It is a catastrophe," Gitta Connemann told the t-online news website.
She argued that the once dominant German political force was on its way to lose the status of a national party and needed "renewal."
"Everything must be reviewed — structures, processes, member participation. There should also be personal consequences," Connemann said.
The latest vote estimates by the ZDF broadcaster point to a tie between the conservative union bloc and the Social Democrats, who are respectively at 24.5% and 26%.