The woman will appear in the High Court at Gisborne late next month.
Police were called at 4.20am on October 28 after reports of a man with severe injuries.
Dewes was rushed to hospital, where he died a short time later.
According to tributes online, he died on the night of his 67th birthday.
A homicide investigation began and this morning police said a murder charge had been laid against the woman.
Earlier today, Detective Inspector David de Lange said police were pleased to have made an arrest.
“It brings some sense of reassurance to the whānau and the wider community. Police would like to thank members of the public who came forward with information.”