Niniwa assembled and was one of two treasurers of a committee to support the Maori language newspapers, Te Puke ki Hikurangi as well as TeTiupiri. Her husband, Kawana Ropiha, was occupied as a chairman and her mother was an associate. Niniwa was the editor for women's affairs, and also established which items of foreign news from English-language newspapers should be translated and contain.
From the late 1890s Niniwa-i-te-rangi stood a position for herself. She was referred to as a leader of Maori affairs alongside such acquiantances as, Wi Pere, Henare Tomoana, Paratene Ngata and Tureiti Te HeuheuTukino. She was the only woman whose views were desired when the Native Affairs Committee inquired into the Native Lands Settlement and Administration Bill of1898.
After the death of her late Husband, Kawana Ropiha, Niniwa married Tamaihotua Aporo. She remained childless in this marriage, despite adopting her husband's daughter and adopting a number of children at birth, whom their descendants regard her as their ancestor.