Hospitals are being urged to adopt a more accurate method of screening new born babies to prevent brain damage.

The babies get screened for low blood sugar, if left untreated it can cause developmental delay, brain damage and learning difficulty in later life.

Currently many hospitals use heel-prick test, but World Health Organisation says it is unsuitable because it is designed to pick up high rather than low blood sugar levels.

Auckland University researcher professor Jane Harding says the alternative more accurate enzymatic test is cheaper in the long run.

"10 to 15 per cent of all babies born will have a low blood sugar level, and if the sugar is low enough for long enough that can cause brain damage."

"Two individual tests are more expensive, but when you add up all of the costs, the analysis we've done in the long run will be cheaper, and so the economic reasons for not using them doesn't hold water."