But Smith said this was only "a good first step" that now needed to be backed up by domestic action.
"Businesses and organisations across New Zealand are taking action on climate change, but to make the changes we need, at the pace we need, this must be backed up by Government action to reduce emissions."
New Zealand emissions had risen by 50 per cent since 1990 and were projected to rise another 40 per cent by 2030 under current policy settings, he said.
"It is urgent that steps are taken to put New Zealand emissions on a downward trajectory as soon as possible."
His organisation wanted to see New Zealand rely less on buying international credits to meet the bulk of its pledged emissions reductions.
One of the letter's high-profile signatories, restaurateur Steve Logan of Wellington's Logan Brown, wanted to see the Government "get stuck in and get on with it".
"We have to put our hands up and take action on climate change so that future generations can also enjoy the quintessential Kiwi lifestyle that we do now."
Others prominent names on the letter include Sir Geoffrey Palmer, Dame Anne Salmond, Sir Stephen Tindall and Bishop Justin Duckworth.
Groups and businesses included the New Zealand College of Midwives, the Anglican Diocese of Auckland, Villa Maria, The Body Shop, The Langham, Les Mills and Ernst and Young.
Bennett told the Herald climate change was "certainly the largest environmental challenge of our time".
She argued New Zealand was making an important and worthwhile contribution to the global effort to combat the problem.
Bennett said the targets the Government had set for reduction in emissions as part of the Paris Agreement were "ambitious and fair".
In other work, the Government was increasing renewable electricity to 90 per cent by 2025, investing $20 million a year in agricultural greenhouse gas research, a further $31 million on research into understanding climate change and its impacts, and up to $200 million in international aid for climate-related support, most of which will benefit Pacific island countries.
In the policy space, the Government was reviewing the Emissions Trading Scheme and phasing out the controversial "one-for-two" measure and establishing three, new, expert groups on adaptation, agriculture and forestry to address climate change.
New Zealand and climate change
• Under present projections, the sea level around New Zealand is expected to rise between 50cm and 100cm this century, while temperatures could also increase by several degrees by 2100.
• Climate change would bring more floods (about two-thirds of Kiwis live in areas prone to flooding); make our freshwater problems worse and put more pressure on rivers and lakes; acidify our oceans; put even more species at risk and bring problems from the rest of the world.
• Climate change is also expected to result in more large storms compounding the effects of sea level rise.
• New Zealand, which this year reported a 23 per cent increase in greenhouse gas emissions between 1990 and 2014 - has pledged to slash its greenhouse gas emissions by 30 per cent from 2005 levels and 11 per cent from 1990 levels by 2030.
