Changes to packaging of popular foods could leave you paying more for less.

A campaign had been launched to block a proposal by the food industry to remove product weights from the front of food packaging.

Consumer group CHOICE is behind the push to block the changes which would allow quantity statements to be printed on the back of products, making them less obvious to savvy shoppers.

“You only have to look at the inconsistent sizing across products from companies like Cadbury’s and Arnott’s to realise how confusing it is for consumers to compare products,” CHOICE media spokesperson Tom Godfrey said in a statement.

For example, according to Godfrey, Arnott’s Tim Tam lovers might be surprised to learn that opting for the caramel variety of the popular biscuits, instead of the ordinary sort, will mean they end up with 25 grams less – otherwise known as two whole biccies.

Likewise, while Cadbury family chocolate blocks may all look the same, their weights fluctuate, Godfrey said.

For example, those buying the Cadbury’s Marvellous Creations range can end up paying the same for a bar that weighs 18 per cent less simply by picking Spider Choc Raspberry over Jelly Popping Candy Beanies.

“The erratic changes in weight across similar looking packs are likely to confuse consumers and illustrate why it’s vital the pack weight stays on the front of a product,” Godfrey said.

“The sad fact is some food companies can’t be trusted when it comes to pack claims and it’s not uncommon to see the size of products reduced but the price remain the same.”

According to CHOICE, the push aimed at The National Measurement Institute is being led by junk food and cosmetic companies who have offered “no good reason for the change” other than that it will remove red tape.

At present, Australian weight and measure laws require quantity statements to be on the front of packets to make them easy to notice, read and compare.

The Department of Industry will consult on the changes until the end of June, in the meantime CHOICE have launched an online petition to stop them.