I too do or should I say did doubt this is a Taiaha. However I have found this New Zealand link which is exactly the same size as my item.
http://www.antiquesreporter.com.au/i...-having-a-car/
I am still very unsure about the type of wood and the finish with a gum/resin lacquer. Also as Stu has mentioned the lack of decoration. I still think it is a weapon though.