A 35-year-old woman has been charged with assault after spitting at police in the Dunedin cells while knowing she had hepatitis C.
Acting Senior Sergeant Trevor Thomson said the woman was initially arrested for wilful damage.
In the cells she spat at two police officers while in processing before she was due to appear in court.
The woman was aware she had hepatitis C, he said.
"She's obviously known to the police," Thomson said.