An elderly woman was indecently assaulted at her home after a man approached her asking for a glass or water.
The assault happened at about 11.30am yesterday in the Nelson suburb of Richmond.
Nelson police arrested a 52-year-old man yesterday.
He has been charged with indecent assault and will appear in the Nelson District Court today.
Detective Senior Sergeant Craig Johnston said the man is believed to have been riding a bicycle around the Richmond-Appleby area and police are keen to hear from anyone who may have been approached by the same man.
Anyone with information should call Nelson police on 06 546 3840.