New Zealand ice cream brand Tip Top has reduced the size of some of its ice cream tubs by 20 per cent, but not the price.

Flavours Goody Goody Gum Drops, Jelly Tip, Monkey Business and Gone Fishin' now come in 1.6 litre containers.

The other flavours remain in 2 litre tubs.

Tip Top said on its website the flavours in 1.6 litre tubs had been packed with more "exciting bits".

The changes were made because other flavours had been "carrying" these flavours for a while, it said.

If all the pack sizes had stayed the same, the price of all products including favourites, would have gone up, the company said.

Market research over the past year had shown consumers bought plainer flavours such as hokey pokey for everyday use and the fancier flavours were reduced in size as they were occasional family treats.

New products Mint Cookie Smash, Brandy Snap and the new range of yoghurt ice creams would also come in a 1.6 litre tub, Tip Top said.

Earlier this year Cadbury reduced its king-size dairy milk chocolate block by 20 per cent and started using palm oil instead of cocoa butter, sparking public outcry.

It later backed down and stopped using palm oil.