This will do wonders for New Zealand firms trying to compete in the global economy. I guess they were not aware of their inherent bargaining power inferiority relative to employers. They didn't realize how much they needed the unions, which they were always free to join, in order to reach bargaining power parity. They must be overjoyed now that Labour Party politicians and unions have enlightened them. As I and others have repeatedly explained, the hoary myth of a worker's inherent bargaining power disadvantage has support neither in logic nor in history.
Bargaining power comes from having alternative employment opportunities.
A prosperous economy within which entrepreneurs and investors are creating increasing employment opportunities gives workers more bargaining power than any union is likely to do. By decreasing the flexibility and resilience of labor and product markets, the ECA will make New Zealand much less hospitable to entrepreneurs and investors, decrease real economic growth, and increase unemployment. New Zealand workers will lose, not gain bargaining power. It is widely understood that unions are labor cartels. A cartel is a group of sellers of something who agree with each other to suppress competition among themselves in order to extract monopoly prices from customers.