Table grape growers say they are concerned that fruit is being sent to market too early and that some immature fruit is putting customers off.
Chair of the Australian Table Growers Association, Richard Lomman, said that as fruit matured on the vine, it became sweeter.
However, as there was an oversupply in the market, everyone wanted to sell first, even if the fruit was not all that sweet.
"This is all being exacerbated by the fact that there's so much fruit," he said. "Fruit is being stored, either on farm or on the vine, or in the distribution centre and we've actually seen fruit from a region that normally finishes in early December, we've seen it on supermarket shelves at the end of February."
Mr Lomman said that the industry was trying to come up with a way to stop the practise of sending fruit below maturity level, but that it could be difficult to do as all fruit did not mature uniformly.
"We've been talking with the major supermarket chains, and they've been responsive, which is great. We've been getting some data for them so that they can understand what's going on," he said.
"We haven't come up with any finite plan yet, but it's a long process and really we believe they're the gatekeepers, so if they're accepting the fruit in there once it's picked, it doesn't sugar up any more."
