The firm has reduced the weight of some packets by almost 15%
Chocolate maker Mars has blamed rising costs for its decision to shrink the size of Maltesers packets.
The firm has reduced the weight of the product's 121g pouches to 103g, a cut of almost 15%.
The decrease was spotted by food retail expert Steve Dresser, who also noticed that packets of Mars' Galaxy Counters have been dropped from 126g to 112g in weight.
It comes a week after Mondelez International announced that Toblerone bars had been reduced in weight by almost 10% to keep costs down.
In a statement, Mars said rising costs forced it to decide between increasing the price of Maltesers pouches or reducing the size of the product.
The firm said: "Like all chocolate manufacturers, we have seen the cost of raw materials rise and, while we try to absorb these pressures as much as possible, sometimes we have to make the difficult decision to reduce the size of some of our products so our consumers can continue to enjoy an affordable treat."
Mars added: "Our focus is always on offering consumers our great tasting, high quality chocolate brands at the best value for money."
In recent years the firm has come under fire for reducing the size of Mars and Snickers bars.