An animal welfare campaign urging people to "ditch dairy" contradicts official nutrition guidelines and has been slammed for advocating an alternative diet which could be detrimental to children's health.

Animal Liberation Queensland is running a new campaign emphasising the suffering that dairy cows and their calves endure so humans can have milk products.

The Ditch Dairy website tells people to cut dairy products from their diet due to the alleged cruelty to cows.

It tells the story of male calf Bobby who is shot at five days old, and his mother Daisy who is killed when her milk supply declines, and argues these cows "miss out on leading a good long life, but you won't miss out on anything by ditching dairy".

The Ditch Dairy campaign also questions the nutritional benefits of dairy. "From a nutritional point of view, there are many reasons to avoid dairy," the website states, citing links between dairy and cancer and heart disease. "There's significant scientific evidence suggesting [dairy] is harmful to your body."