As news items go, it was easy to miss. The press release in February briefly announced that the police were introducing the Taser stun gun this year (due in September).

The populace of Auckland City, North Shore/Waitakere, Counties Manukau and Wellington were selected as the lucky guinea pigs for "trial" tasering.

The police have been strangely silent on how the Taser works and what it does to people. They have tried to paint the Taser as benign, saying it uses a mere "5 watts of voltage".

That is misleading. In fact, the Taser applies to its victim a 50,000 volt shock, of five seconds duration, each time the trigger is pulled.

The shock causes involuntary spasm of the major muscles and excruciating pain. The victim collapses, inert.

The Taser works in two modes. It fires two barbed darts from up to 6m.

If the barbs penetrate their target, the shock is administered through trailing wires. Alternatively, it can be held against the victim and fired.

The Taser's manufacturer, US corporation Taser International, has aggressively marketed its product worldwide, with great success. It promotes the Taser as "safe and effective".

Our police are taking the same line, promoting the Taser as "an additional, less-lethal tactical option", and safe. In the New Zealand context, this begs the question: safer and less lethal than what?

The "less-lethal alternative" argument may apply in countries such as the United States, where the police carry firearms and routinely use them on suspects.

But not in New Zealand, where the police are not routinely armed.

Crucially, the New Zealand Police are not introducing the Taser as an alternative to the use of firearms. Instead, the aim is to provide the weapon to officers on patrol.

Thus the press release is thoroughly misleading on another crucial point. It proclaims that "New Zealand Police will follow the British path".

In Britain, the Taser can only be used by trained firearms officers, in situations where the use of firearms is also authorised - in other words, as a genuine alternative to use of lethal force. That is not what is proposed here.

In March, Amnesty International issued a detailed report on the use of the Taser in the US. It records that since June 2001, 152 people have died after being shocked by a Taser.

Each year in succession, the number of "Taser-related deaths" has greatly increased, for example, from 17 in 2003 to 48 in 2004 and 61 last year.

Amnesty does not claim that each of the 152 deaths was demonstrably caused by the use of the Taser. But Amnesty - and others - express serious safety concerns.

The claim that the Taser can kill is founded on the ability of the shock it delivers, particularly if repeatedly administered, to cause an uncontrollable spasm of the heart muscles, or "ventricular fibrillation", resulting in a disruption of the heart's pumping function and death by cardiac arrest.

Cardiac arrest is the reason for many, if not most, of the Taser-related deaths.

Taser International's defence is invariably that the true cause of death was something other than the use of the stun gun.

Is the Taser safe for use against New Zealanders? There is little independent research into the effects of its shock on susceptible individuals.

Taser International relies on studies involving the administration of Taser shocks to pigs and resting healthy human subjects.

But the individual case studies recorded by Amnesty International demonstrate that the greatest risks arise where the shock is repeatedly administered to highly agitated individuals and/or those with existing health problems.

Yet these are the people against whom the Taser is most likely to be used.

Our police have made this plain, identifying as the intended targets "unarmed (or lightly armed), but highly aggressive people; individuals in various states of mental health crisis; and people under the influence of mind-altering substances, solvents or alcohol".

While its potential lethality is critical, the Taser has other bad points. First and foremost, the Taser is a gun. In making it standard issue for police, we would be arming them for the first time in our history.

No case of compelling need to take this step has been put forward, let alone made.

Next, the Taser causes immediate, potentially serious injury if a dart penetrates the victim's body. The darts require surgical removal, and if one penetrates the eyeball it will cause major injury.

Furthermore, the Taser regularly causes a range of injuries associated with falling while unconscious. Such injuries can be serious.

A Taser shock may cause a pregnant woman to miscarry. All these significant risks and others are conceded by Taser International in its product warnings.

Finally, the Taser's shock is, by all accounts, excruciatingly painful, humiliating and distressing. There are accounts of the Taser being used as a torture weapon by American solders in Iraqi prisons.

Is this the kind of weapon with which we want our police to be armed? And why has all this known adverse information not been publicly disclosed by the police?

In response to this, the police will no doubt say there will be guidelines imposed; that its use will be carefully monitored; and that the New Zealand police are different, and can be trusted not to misuse the weapon.

Put that argument to any criminal defence lawyer and almost any ex-policeman, and you will get a Tui billboard response, "Yeah right".

There is mounting evidence that the police cannot be trusted to correctly use the pepper spray which they already have.

Thanks to the recent Budget, we can expect to see 1000 new and inexperienced police employed over the next three years.

Do we really think that an 18-year-old constable, for example, issued with a sophisticated "toy" such as the Taser, will not use it at the first available opportunity?

And experience shows that use patterns for police weaponry easily "creep" towards abusive lower thresholds, as has happened in the US with the Taser, and here with pepper spray.

Given its effects, I contend that Taser use by our police will contravene the Bill of Rights. It constitutes cruel, degrading or disproportionately severe treatment or punishment, and failure to treat a person deprived of liberty with humanity and with respect for his or her inherent dignity.

These are no wishy-washy concerns. Lord Cooke, arguably our greatest judge, has described the right not to be subjected to inhuman treatment as a "right inherent in the concept of civilisation".

Ultimately, the fundamental question posed by the Taser's introduction concerns our national identity: what kind of a society do we really want?

New Zealanders view themselves and their collective security in ways which are unique. We are nuclear-free, and proud of it.

Most importantly, our police are not routinely armed, and we expect them to show tolerance, maturity and restraint rather than resort to weapons, even in situations of crisis.

Does the Taser have a place here? Please join me in a resounding "No".

* Dr Rodney Harrison is an Auckland Queen's Counsel.