The situation in New Zealand may be somewhat different. Here in Germany, the exploited sex-workers are often trafficked from eastern europe or even farther away

The situation in New Zealand may be somewhat different. Here in Germany, the exploited sex-workers are often trafficked from eastern europe or even farther away. That would be hard with New Zealand being islands at the end of the world. You may also underestimate the size of the exploitative "market segment". And sometimes the line between consent and exploitation is blurry.