In pre-European times the base of the cloak was made from flax fibre (muka) which had been washed, bleached to almost white and then softened. The fibres would then be rolled together until a long yarn was formed, which was woven into a large rectangle forming the backing of the korowai. There are very few weavers who still use this method.

The feathers were fastened onto the backing.  The most prized feathers were from the huia and kiwi, especially the rare white albino kiwi. Sometimes the cloak would be fringed with taniko (a type of stitching) or white kiwi feathers. More colourful cloaks were made from the feathers of the wood pigeon (white feathers from the breast and green from the back), kaka or native parrot (red feathers) and tui (blue-black feathers). 

The few remaining korowai that were made with these traditional materials are priceless taonga (treasures) and are commonly stored in museums.  These korowai are not easily accessible for most people.