She believed the remains to be about 200 years old and that the young woman had died and been buried "naturally''.
The remains appeared to have been placed in a traditional foetal position.
There was also evidence of "large'' animal bones in the same spot, and indications of cooking sites.
The bones were likely to have come from a large sea mammal, she said.
"It is very important that we become aware of these sites so that if people do come across them they do the right thing - don't assume buried bones are probably just animal bones.''
Similar finds had been made over the past few years during foundation work under the Department of Conservation building on Marine Parade and near the Te Pania Hotel.
She said anyone excavating and coming across such a find should contact the police and the Historic Places Trust.
Ms Pishief had spoken to Simkin Construction boss Terry Simkin and he had assured her that if any other items were unearthed at the site (although most of the area had now been excavated) she would be notified.