Chief Constable Sir Hugh Orde tonight faced new demands to abandon any plans to arm police in Northern Ireland with 50,000-volt stun guns.
As British home secretary John Reid announced specialist teams within British forces could soon be equipped with the controversial Tasers, Amnesty International warned it could lead to officers being routinely handed the electro-shock weapon.
Sir Hugh is currently considering whether to introduce Tasers in the Police Service of Northern Ireland, and a decision could be taken within months.
But the human rights group urged him to carry out more safety checks.
Spokeswoman Fionna Smyth insisted: "Tasers are potentially lethal weapons.
"Amnesty International has studied the use of Tasers in the US and Canada, where more than 220 people have died since 2001 after being 'Tasered'.
"Amnesty wants assurances from the Chief Constable, Sir Hugh Orde, and the Northern Ireland Policing Board that they will not introduce these weapons here until comprehensive and independent testing can establish that they are safe.
"Even then they should only ever be used by trained firearms officers."
Tasers, only used in Britain by specially trained firearms officers facing an armed threat, deliver electric shocks to temporarily paralyse their target.
Mr Reid told a Police Federation Conference in Blackpool that a year-long pilot would begin this autumn, subject to medical approval.
His department wants the guns, seen by many as a less dangerous alternative to firearms, made available to police units such as tactical support teams and drugs squads.
The trial is set to involve a number of forces in England and Wales.
"You deserve our protection," Mr Reid told the Federation.
"I want them to be available to other specially trained teams — not just firearms officers — sent in to deal with severe violence or threats of violence. "I hope that from September this year we can start a trial."
A PSNI spokesman pointed out how forces in England, Wales and Scotland have deployed Taser operationally since April 2003, while the Garda were given the authority to purchase and use Taser last month.