Helping a N Z Friend Who is Looking for Her Maternal Aunt Who Married an American IN N Z Then Moved to Queensland a Remarried There

She divorced in 1962. Her name was Zita Alice LUCAS - born 23-9-1923 in Wellington N.Z. Her parents were Robert John Percival LUCAS and Maude Beatrice nee RIDGWAY. We have been looking for Zita for over 40 years as she still has an elderly sister alive and living in N.Z. who would like information.
Any help would be great.