Prosecutors have cited the fugitive disentitlement doctrine of law in arguing that Polanski must appear or be barred from having his motion heard. Hummel argued that, before he fled the country, Polanski - whose films include "Tess," "Chinatown" and "Rosemary's Baby" - signed a waiver of his appearance at all hearings in the case.
District attorney's spokeswoman Sandi Gibbons said Tuesday that the waiver was signed before the sentencing hearing from which Polanski fled three decades ago.
"The waiver does not count anymore," she said. "There is a warrant out for his arrest."
Prosecutors say there should be no hearing if Polanksi is not present.
Complicating matters further is an affidavit filed Monday by the rape victim, Samantha Geimer, now 45, who wants the case dismissed in order to stop renewed waves of publicity.
Geimer, now a wife and mother of three who has been public about the case since 1997, said she feels she is being victimized anew by prosecutors who recite the "lurid details" of her assault in their legal papers.
Hummel argued that California's constitutional amendment known as the Victim's Bill of Rights "expressly recognizes the importance of achieving finality in a criminal proceeding that has hurtful consequences for a victim, her family and loved ones."
Geimer has volunteered to come and speak at the hearing.
Gibbons said prosecutors would have no comment on Geimer's affidavit.