The Government was today criticised for passing a "farcical" law which appears to make it illegal for people to have mobile phones in their pockets while driving.
Drivers caught holding a mobile phone will be fined €435 and a third offence carries a maximum prison sentence of three months.
The law was introduced to stop the "inherently dangerous" practice of making and receiving calls on the move, although "hands-free" phones are allowed.
Fine Gael questioned a section of the regulations which banned people from having mobile phones "on or about their person" while driving a vehicle.
Mr Denis Naughten accepted that action was needed to stop the dangerous practice but said the regulations were "riddled with confusion and ambiguities".
"The Department of the Environment confirmed it will now be illegal to have a mobile phone in your pocket while in the car but perfectly legal to have it on the seat or in the glove compartment beside you," he said.
"The measure used to implement this new law is farcical."
He said the legislation "will criminalise a driver who has their mobile phone turned off in their pocket and leave them facing a sentence".
Mr Naughten was referring to paragraph four of the new regulations which today officially became law.
The paragraph states: "The driver of a mechanically propelled vehicle that is in a public place shall not hold or have on or about their person a mobile phone or other similar apparatus while in the said vehicle except when it is parked."
Minister of State at the Department of the Environment Mr Robert Molloy, said: "The safety of road users simply has to come first".
Although hands-free kits will not be illegal under the law Mr Molloy said he would keep this under review.
"There is some scientific evidence that using any mobile phone is a distraction for a driver and I would prefer to see all drivers stopping in a safe place to use their phones," he said.
PA