What is sustainability? According to a new report by KPMG, whatever retailers want it to be.

The company has released its report on the definition of sustainability in the marketplace, and found that criteria change based on what retailers can afford to say, and what they think their customers want to hear.

KPMG agribusiness partner Ian Proudfoot says that often comes down to perception, and what retailers think will play well with consumers.

“We are trying to use science to demonstrate that the practices we have are sustainable.

"I think we’ve done that quite well, with the food mile situation, the research that’s been done on that has proven a sheep coming out of Southland to London can be delivered on shelf with the same carbon footprint or less than a sheep coming out of Wales.

Mr Proudfoot says New Zealand suppliers can’t afford not to fit with what retailers define as sustainable.

"We need to have the trade bodies in the industry understanding that there is a societal change taking place.

"There is a move towards people wanting to have sustainable product, although it is a difficult thing to define.”