Tuila'epa Sa'ilele Malielegaoi was commenting following a report of the president, Fepulea'i Attila Ropati, changing his mind, saying he would stay in the job.
He had earlier told the chief justice he would resign after being convicted of assault by the Court of Appeal.
The prime minister said parliament had powers under the constitution to remove a judge by a two thirds majority.
Since the president's conviction in the court of appeal a week ago a government vehicle he had had access to has been returned to the Ministry of Justice and his salary has been stopped.
