Environment Minister Nick Smith touches down in Paris late today, to chair the fourth yearly meeting of environment ministers from OECD countries.

Major issues up for debate include water, climate change, air pollution, and resource use.

Dr Smith said in the wake of the Paris Climate Agreement, many countries will be comparing notes on how to achieve their targets.

"There will be a lot of discussion around electric car technologies and how governments can maximise its uptake. Things that we need to do more broadly in the urban planning area, and particularly crucial for New Zealand is agricultural emissions."

He said they won't shy away from the tough topics.

"Quite a focus on a number of countries, like New Zealand, that have problems with the build up of nitrogen from agriculture and the impact that is having on our waterways."

Green Party co-leader James Shaw said agriculture is our biggest problem, and solutions are starting to emerge, but we need to do more than just talk about them.

"Actually there's hope that we can have a high value, high productivity agricultural sector that also reduces greenhouse gas emissions and cleans up rivers as it goes."