Police, who will release the report, refused to confirm the release date.
The report is the result of a three-year inquiry into the crash by former Metropolitan Police chief Lord Stevens.
Diana, 36, and her friend Dodi Fayed, 42, were killed along with chauffeur Henry Paul when their Mercedes crashed in the Pont d'Alma tunnel in Paris on Aug. 31, 1997, while the couple were being chased by media photographers.
Rumors and conspiracy theories continue to swirl around Diana's death, despite a French judge's 1999 ruling that the crash was an accident. An investigation later concluded that Paul had been drinking and was driving at high speed.
The British inquiry, which is estimated to have cost as much as $7.2 million, employed cutting-edge computer technology to reconstruct the crash scene, and examined the Mercedes in painstaking detail.
Former senior judge Lady Butler-Sloss, who is coming out of retirement to preside at the inquest, has written to the legal firm Farrer & Co. that represents Queen Elizabeth II and her family.
The inquest, which was initially convened and swiftly adjourned in 2004, is due to formally resume next year.
At the preliminary hearings, the judge will decide whether Diana and Fayed will have a joint inquest and whether there will be a jury.
The palace said it had received Butler-Sloss' invitation to attend the preliminary hearings.