The price difference between A brands and private labels in the supermarket has also grown further in the past year. Private label products are now on average almost 50 percent cheaper, according to a study by the Consumers' Association on Tuesday.

The difference has been increasing for years. In 2014, private labels were still 24 percent cheaper, now it is 45 percent.

Especially when purchasing detergents and dishwasher tablets, it pays to reach for the shelf with the private label. Ariel washing powder costs on average almost 80 percent more than the own alternative at the supermarkets studied.

The price difference is greatest at 48 percent at Deen, Deka, Dirk and Vomar. The price difference is the least at 39 percent at ALDI and Poiesz.

According to the Consumers' Association, the price difference can partly be explained by the fact that in some supermarkets the house brands merge with the even cheaper budget brands. Albert Heijn and Jumbo are at the forefront of that strategy.

The research also shows that discount supermarkets have also started offering more A-brands. ALDI has 150 on the shelves and Lidl about 30. These products are not cheaper than at other supermarkets at the discounters, according to the Consumentenbond.