TMZ said Lohan, 26, was not in court Monday morning for the first scheduled hearing in her November nightclub assault case.
The "Liz & Dick" star was arrested and charged with misdemeanor assault after she allegedly punched a woman in the face.
"The investigation into this case is continuing," TMZ quoted an unnamed prosecutor as saying.
The actress' attorney, Mark Heller, has dismissed the assault claim, contending that Lohan is "a victim of someone trying to capture their 15 minutes of fame."
The former child star's once-bright career has been eclipsed in recent years by her legal and financial woes and her battles with drugs and alcohol.