Ms Bennett said the signing ceremony at the United Nations on April 22, which 130 countries will participate in, was another step towards ratifying the Paris Agreement.
There is no deadline for the ratification, which covers emissions obligations after 2020 and commits all countries to limiting global temperature rise to 1.5degC this century.
Once the agreement is ratified, Ms Bennett said, the more difficult task of moving New Zealand to a low-emissions economy would begin.
"Quite frankly, there's some easy ways to do that, and there's some harder ways. And I want to go down the harder path to start with."
Nearly half of New Zealand's emissions come from agriculture, and the Government is investing in technology to cut these emissions.
In the meantime, it is likely to meet its obligations by buying carbon credits and seeking cuts in the transport sector - partly through encouraging electric vehicle uptake.
The Government has set a target of cutting its greenhouse gas emissions by 11% below 1990 levels by 2030.
In Parliament yesterday, Ms Bennett said she was considering the creation of a taskforce to help develop a plan for New Zealand to meet its obligations.
The Paris Agreement will take effect once 55 countries, accounting for at least 55% of global emissions, have submitted their ratification instruments.
