Several beverages derived from cereals, legumes or nuts or a combination of these products are available on the market as dairy milk alternatives. These beverages are made from:

legumes such as soy
cereals such as rice or oat
nuts such as almond.
Are plant–based milk alternatives suitable for use as a complete milk replacement?
Generally, plant-based milk alternatives don’t have the same nutrient content as cow or goat milk. Milk generally contains higher levels of protein and a wider range of vitamins and minerals.
Legume-based beverages, such as those made from soy, can contain added vitamins and minerals if they contain a similar level of protein to milk (at least 3%).

Cereal, nut and seed-based beverages, such as those made from rice, almonds or sesame, are lower in protein than legume based beverages and dairy milk. Some of these products are supplemented with added protein usually from a legume source.

These beverages are permitted to have vitamins and minerals added in amounts similar to milk. You can check the label for:

the amount of protein in the Nutrition Information Panel

amounts of vitamins and minerals – if they contribute at least 10 per cent of daily requirements per serving, they could also be listed.

Why do plant-based beverages have an advisory label?
Children need sufficient protein and energy for normal growth and development. If beverages like almond or rice beverages are a regular part of a young child’s diet, other food sources of protein and energy need to replace the protein and energy otherwise provided by milk. Plant-based beverages that contain less protein than milk are required to have advice on the label that the product is not suitable as a complete milk replacement for children under 5 years old. Milk products and plant-based milk substitutes that have adequate protein but are low in fat are required to carry an advisory statement on the label that the product is not a complete milk replacement for children under 2 years of age.
Who should I contact for more information?
Talk to a dietitian or doctor if you are considering drinking plant-based beverages, or giving them to a child as an alternative to milk. Also, note that these products are not suitable for anyone allergic to the substance(s) from which the beverages are derived, such as soy or oats. Young children with an allergy/intolerance may be advised about a hypoallergenic formula, which is suitable as a complete milk replacement.

For dietary advice contact the Dietitians Association of Australia or the New Zealand Dietetic Association.

http://www.foodstandards.gov.au/consumer/nutrition/milkaltern/Pages/default.aspx