A 50cl Smirnoff red bottle is being trialled in the cash and carry and convenience sectors from March in UK.
Diageo said that fractional sizes such as 35cl did particularly well in the vodka category and predicted the new size would appeal to people doing top-up shopping.
Senior brand manager Helen Facey said: “We have made the decision to trial this new 50cl size for Smirnoff as there is a proven consumer demand within the fractional category and we expect the product to perform well.
“We want to be able to offer consumers a range of options and price points, so that they can choose the size that best suits their needs for different occasions.”
The recommended selling price is GBP 9.49, but an GBP 8.99 price-marked pack has been introduced for the launch period. Once Diageo GB evaluates the results of the trial, a decision will be made on a permanent launch.