Canterbury dairy company Synlait is producing a new milk powder to help people with sleeping disorders.
Synlait Night Milk is made from milk collected from cows during the hours of darkness and is processed at the company's new nutritional plant in Dunsandel.
It is one of a number of initiatives by the company since it opened the $100 million plant late last year.
General manager for market and product development Tony McKenna says cows produce a sleep-promoting hormone called melatonin at night and, just as with human mothers, that hormone is expressed in milk.
Dr McKenna says the company has identified a market for the product in Asia and Europe, with key consumers likely to be professional people, the elderly and international travellers.
The milk could be on supermarket shelves by the end of this year, he says.