The study, published in the British Medical Journal and carried out by the US-based Insurance Institute for Highway Safety (IIHS), claims in-car devices do little to improve safety.
It is thought that the survey, which examined drivers in Perth, Western Australia, is the first detailed examination of links between phone use and road accidents.
Under UK law, using a mobile phone while driving is a criminal offence - unless it is fitted from a hands-free kit.
"You'd think using a hands-free phone would be less distracting, so it wouldn't increase crash risk as much as using a hand-held phone," said Anne McCartt, vice-president for research at the IIHS. "But we found that either phone type increased the risk."
Researchers studied 456 drivers in Perth who used mobile phones and required hospital treatment following a crash between April 2002 and July 2004.
The study examined each driver's phone records in the 10 minutes before the crash and compared it to similar journeys taken 24 hours, three days or a week before their accident.
It found there was an overall fourfold increase in injury-causing crashes when drivers were using mobiles.
The study found that male and female drivers faced the same increased risk of accidents by using a phone, along with drivers both under and over 30.
Motorists caught using hand-held phones while driving in Britain face a £30 fine, which can rise to £1,000 if the matter is taken to court.
Police can also prosecute those using a hands-free phone if the driver is considered to have lost proper control of their vehicle.
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