Olsen Family

My maternal great great grandmother Olava Olsen who was born in Christiana in 1862 emigrated to New Zealand and married Wilhel\m (William) Frans (Francis) Anderson (born Gottenburg, Sweden) in 1884. Olava's parents (according to the information on her NZ marriage certificate) were Berta (nee Christiansen) and Christian Olsen. I am try to trace how and when Olava came to NZ -ship and date and also wether she was accompanied by her parents. Did she come here with siblings? - a Lena Olsen was a witness to the marriage. Olava died in Wellington in 1929 and her husband remarried in 1931.