Born Feilding Sep 12, 1959 male looking for contact

Hello everyone, I have been trying to make contact with my birth mother or father for many years, off and on. My birth mother has vetoed any information about herself, and I respect that. However I now have children of my own and I believe I owe it to them and myself to try and gather some history in the belief that every person has a moral right to know where they came from. My mother had red hair, caucasen, separated and was about 32 years old in 1959. My father had a stocky build, part Maori, about 30 years old and was a labourer. I was named John on the birth certificate I received from the Social Welfare Dept. As I said I am looking for information, however contact would be fantastic. So, any help would be greatly appreciated.