Of those surveyed at the event, almost 10% said sustainability is negotiable, while 21% said maybe.
Some 46% also said they are confident that the UK can lead on sustainability, while 15% answered no and 38% said maybe.
The Sustainability Events Summit 2014 took place at 30 Euston Square yesterday (18 February) and was attended by more than 120 event planners, agencies and venues.
Talking at the event, Dan Germain, head of creative at Innocent said: "Sustainability is part of a concept called trust and it’s for this reason people buy from us."
The Summit closed with a plenary session with Olympic Gold Medallist Etienne Stott MBE and Lucy Siegle, presenter of the BBC's The One Show.
Etienne Stott MBE said: "In my sport we focus on the small details of how to make a canoe go faster. This means simplifying everything down into easy-to-make decisions. People can only make the choice to implement sustainability if it’s presented as a simplified concept.
"Once you cut through the bewilderment you can decide where to make the biggest impact. Then you can drill down into the small details that make all the difference."