"She has been told the fractures are stable and therefore she doesn't require surgery and is expected to make a full recovery," he said.
Mr Oatham said he expected Ms Whiteside would remain in Tauranga Hospital for the next few days before being transferred to Auckland Hospital.
"She is likely to be in a neck brace for a quite little while when she is discharged. But when I spoke to her she seemed quite bright considering the injuries she's suffered," he said.
Mr Oatham said it was still unclear what had caused the accident.
"Because of the concussion Jenny suffered she can't recall it happening but that's not unusual as quite often riders who fall heavily aren't able to say what happened.
"While we did speak to the other riders in the race and viewed the video footage, at this stage the outcome of our inquiry is inconclusive."
Fellow jockey, Vinnie Colgan, sustained bruising when his horse fell over the top of Ms Whiteside's mount during the collision.
Yesterday he was still feeling the after-effects of the fall and had taken a few days off, Mr Oatham said.
The third jockey, Craig Grylls, who was also thrown from his mount, flew out of the country yesterday to continue competing overseas.