Sunday's 4-2 defeat at home to Parma, their third successive domestic loss, saw Milan slide to 11th in the Serie A table, a staggering 40 points behind leaders Juventus.
They have also crashed out of the UEFA Champions League at the last 16 stage after a 5-1 aggregate defeat at the hands of Atletico Madrid.
That had led to protests from supporters and reports that former Milan midfielder Seedorf, who was only appointed as Massimiliano Allegri's successor in January, could soon be replaced.
But Berlusconi has moved to back the man currently in the hot-seat and attempted to shift the blame for the current malaise on to previous incumbents.
He told SkySport24: "Seedorf is not up for debate.
"He will still be the Milan coach next year. Milan are a badly built team."