Police in Christchurch are treating a recent serious assault in the suburb of Linwood as a homicide, following the death of the victim.
Michelle Lawrence, who was 41, had been in hospital since being attacked in the early hours of the morning three weeks ago.
Police have charged Timothy Foley, 52, with wounding with intent to cause grievous bodily harm, and he will reappear in court on Tuesday.
Police say additional charges are likely to be laid now that the case is a homicide investigation.
A post mortem will be carried out on Monday.