Australia's consumer watchdog is to clamp down on the A$150m juice bar segment of the annual A$1bn fruit juice industry.

The Australian Competition and Commission said it is concerned about misleading nutritional, health and therapeutic claims.

"The ACCC wants to see an overall improvement in trade practices law compliance at every level of the industry - from packaged juices in supermarkets and convenience stores through to the exotic juice bar blends," said ACCC chairman Graeme Samuel in a statement.

"These claims about certain ingredients may not exist, cannot be substantiated or in fact may adversely impact on a consumer or their diet," Samuel added.

The ACCC said that it has written to juice bar companies, outlining their legal obligations.