Level Environmental playing fields

I do strongly believe in ensuring our environmental position is maintained and improved BUT to then allow goods manufactured with lesser controls without penalty into our country is not a level playing field. If we force a manufacturer to implement controls on their plant in NZ then we should apply tariffs to overseas manufacturers who do not have the same constraints on their manufacturing process. Effectively what we currently do is force "dirty industries" to clean up then hit them with a double whammy that ensures they are not competitive with their dirtier overseas competitors. i.e. the overseas supplier has lower costs because they have not had to spend on emision control this will drive the NZ company offshore and promote less effective environmental controls. This is not really NZ being a good global citizen. I wonder if this is the future for the dairy industry with regard CO2 emissions... (Fontera are already investing overseas) Are we going to penalize the dairy industry to a point where its cheaper to import milk probably from countries where by shutting down coal plants they will be able to offset carbon credits...(we are already importing dutch milk powder). Seems NZ will be penalized in the same way for leading the world in renewable energy i.e. we cant close coal plants..