The maker of Marlboro cigarettes has bought the rights to a tobacco-free "cigarette" which a New Zealand researcher says will not kill its smokers.

The purchase by Philip Morris International follows rival British American Tobacco's moves to develop a safe alternative to tobacco.

The Philip Morris device - a nicotine pyruvate inhaler invented in the United States - underwent initial testing in 2009 by Health NZ and the Christchurch Clinical Studies Trust.

Christchurch public health physician and Health NZ managing director Dr Murray Laugesen, who also conducts research on electronic cigarettes, said the device would give those addicted to nicotine a safe option.

"It's the best product so far that can rival a cigarette. If it was in the market already at the right price it would outclass cigarettes. In 10 puffs it delivers sufficient nicotine like a cigarette."

He said the device was likely to become "a life-saving smoking substitute" which smokers would be happy to adopt.

"The nicotine pyruvate inhaler-cigarette has potential as a rapid, safe and pleasant way for smokers to obtain nicotine."

He welcomed Philip Morris buying the rights to the device.

"They've got the global capability to market it and the deep pockets required to develop it," Dr Laugesen said yesterday.

Smoking diseases are thought to be caused mainly to the toxins in the smoke, rather than nicotine.

Around 20 per cent of New Zealand adults smoke.

Smokers on average die about 10 years prematurely and the habit kills about 5000 New Zealanders a year.

Philip Morris and British American Tobacco (BAT) say they want to reduce the harm associated with tobacco.

As tobacco is placed under increasingly strict regulation and taxation, tobacco companies also face declining sales.

BAT predicted the market for cigarettes - excluding China, which is largely closed to foreign tobacco companies - was likely to fall by 2.5 per cent this year. Tobacco sales slumped 10 per cent in New Zealand last year after a tax increase.

BAT announced last month the creation of a new company, Nicoventures, to develop and commercialise nicotine delivery products.

It said the company's aim was to provide smokers with a range of alternative products "that will offer much of the experience they expect from a cigarette but without the real and serious health risks of smoking".

BAT is expected to announce details of a new device soon.

Today is World Smokefree Day.

* Liquid nicotine and pyruvic acid mix in a chemical reaction to form nicotine pyruvate.
* Pyruvic acid used as an aerosol to carry the nicotine to the lungs.
* It occurs naturally in the human body.
* Device powered by inhalation - no heating.
* Prototype shaped like cigarette but larger.
* Will be miniaturised for sale.
* Inventor expected commercial sales by 2015.