The use of Tasers by police forces in England and Wales has more than doubled over two years, raising concerns from lawyers and human rights groups.
Stun guns were used 7,877 times in 2011, compared to just 3,129 times in 2009, Home Office figures released on Tuesday revealed.
However, the percentage of uses where the Taser does not make contact with the suspect, such as when it is drawn and aimed so a laser red dot is placed on the subject, has consistently remained between 72% and 75%.
Kate Allen, the director of Amnesty International UK, said the increasing roll out of Taser guns was a "grave concern".
She warned stun guns are "not a modern truncheon" and said only small numbers of officers should be trained in their use.
"A Taser doesn't just give a little tingle - it's a potentially lethal 50,000-volt weapon and should not be spoken of as some sort of 'natural progression' of the standard policing kit."
In 2004, following a trial in five forces, it was agreed to allow chief officers of all police forces in England and Wales to make Taser available to authorised firearms officers.
There have been a number of controversial cases involving use of the stun guns - including blind pensioner Colin Farmer who was hit with the weapon in Chorley, Lancashire, when an officer mistook his white stick for a Samurai sword.
In 2009, 23.2% of Taser deployments involved the stun gun being fired, as opposed to just drawn, while this dropped to 20.4% in 2010 and then rose slightly to 20.8% in 2011.
In April this year Andrew Pimlott died after being burned when he doused himself in flammable liquid and was then hit by a Taser outside his Plymouth home.
Solicitor Jules Carey, who represents a number of clients taking legal action over stun gun use, said the range and volume of weapons available to police has risen consistently since 1995, despite falling crime.
He said: "It is not merely the size of the police arsenals that are of concern to the public, it's a general lack of confidence in police officers using the weapons appropriately, or having the judgment to assess what constitutes a proportionate response.
"Tasers are serious weapons and are not always 'less-than-lethal' as originally intended. They should never be used in routine policing - for instance, to make restraint easier.
"They should only be deployed in the most serious of situations, if necessary and as an alternative to lethal force."
But President of the Police Superintendents' Association of England and Wales Irene Curtis said the stun guns can mean fewer officers and members of the public are hurt.
"It is not a surprise that the number of deployments has increased because the number of people with access to Tasers has increased in that time," she said.
"We support the roll-out of Tasers. We think it's a really useful tool that officers can use and can help reduce injuries to the public and to police officers.
"A Taser used appropriately can reduce the amount of time that officers need to have off because it reduces injuries. It reduces harm to the public because if there's a dangerous individual, they can be restrained more quickly.
"And sometimes the only other option is firearms. A Taser isn't a gun. A Taser can in some circumstances cause less harm than striking someone with a baton."Suggest a correction