"The Fonterra fiasco this week demonstrates how fragile our environmental image is - and that image is of great value to us."
It comes just a week after data from the Ministry for the Environment showed it was unsafe to swim at nearly two-thirds of monitored recreational sites on New Zealand rivers.
Another keynote speaker, Dr Angel Hsu, of Yale University's Centre for Environmental Law and Policy, cited a 2012 international report to show how the country ranked against others.
While it rated highest out of 132 countries in east Asia and Pacific region and placed 14th worldwide, New Zealand scored below average for its fisheries (28 per cent) air (39 per cent) and water resources (40 per cent).
Professor Ralph Sims, of Massey University's School of Engineering and Advanced Engineering, gave his own report card when it came to our energy performance and efficiency, awarding just an overall half-mark.
He said New Zealand was the only developed country not to have pledged a target to reduce its carbon emissions. "Other countries have stayed committed and the only way that New Zealand can save face is if it comes up with a stringent target and says it can deliver on that."
If not for the off-setting effects of its forestry, the country wouldn't be "anywhere near" its Kyoto Protocol target to get greenhouse gas emissions back to 1990 levels, he said.
Professor Sims, however, gave the country a four-out-of-five for achieving two-thirds of its electricity generation through renewable energy.
A presentation on the state of our freshwater system gave a varied picture, with quality in most measured categories worse in urban areas.
Alastair Bisley, chair of the Land and Water Forum, said most Kiwis had shown concern that "our water is not as good as it should be".
His group had recommended regions collaborate to address the problem, adding that the economy had to be a consideration.
Massey University freshwater ecologist Dr Mike Joy said a "huge change" was needed to clean up waterways, namely steering away from intensive farming. "Before you start changing direction, you've first got to put the breaks on - and we are going down the road of just more taking from the environment."
Environmental Defence Society chairman Gary Taylor felt the country had to make many improvements if it wanted to keep trading on its clean, green brand.
"We need to get some better science in order to measure how well we are doing, and in many areas, the policies just aren't cutting the mustard," he said.
By the numbers
14th
New Zealand's most recent worldwide ranking according to the Environmental Performance Index.
2.5
A ranking out of five for New Zealand's energy efficiency and performance, given by Massey University's Professor Ralph Sims.
61%
Proportion of monitored New Zealand recreational river sites rated poor or very poor by new government data.
