Beauticians can set themselves up in business with cheap Chinese laser machines costing as little as £1,600, without having to receive any safety training, they say.
In October 2010 regulations, widely seen as unnecessarily burdensome, that regulated the use of laser machines for 'cosmetic' procedures were scrapped.
Stanley Batchelor, a laser protection specialist, said: "It was over-regulation, to be honest, but now we have gone full-swing."
There are now about 10,000 private clinics offering cosmetic laser treatment to remove facial hair, 'wine stain' skin patches and unsightly thread veins.
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But in England, there are few areas outside London with regulation at all.
Mr Batchelor, Professor Harry Mosely, president of the British Medical Laser Association, and Graham Hart, of the Society for Radiological Protection, said they were aware of many cases where people had been scarred by lasers operated by poorly trained people.
Prof Mosely said a single flash of a laser could cause blindness, if it burnt the retina, and there had been cases where people had lost sight in an eye as a result. Other instances included a woman left with a hole in the skin of her forehead.
He said: "If used inappropriately the laser can inflict significant damage."
A 2008 Department of Health assessment concluded de-regulation carried "minimal risk" of increased injuries, although it also estimated the NHS would face a £1.8 million bigger bill to help clear up when cosmetic procedures went wrong.
Prof Mosely thought this figure an underestimate, and added: "What concerns me more is the impact on the client, scarred for life. This is not a cost that anybody should have to bear."
People seeking cosmetic laser treatment currently had little way of knowing if a clinic was safe, they warned.
They want a simple way of regulating or accrediting clinics to ensure they meet minimum standards, perhaps policed by local councils as they are in London.
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