The proposal to ban the use of hand-held mobile phones while driving is riddled with confusion and ambiguity, according to Fine Gael.
Mr Denis Naughten TD described it as "Bull Island politics".
"It is blatantly obvious that the Minister has no competence in addressing the road safety issue when he cannot implement a simple practical measure - which every sensible person welcomes - without creating confusion," he said.
Mr Naughten said the Minister had used a sledgehammer to crack a nut while ducking the key issue of a penalty points system.
Mr Molloy issued a statement yesterday afternoon in which he "clarified a number of issues" in relation to the ban on drivers using mobile phones.
According to the regulations, a driver of a mechanically propelled vehicle in a public place, "shall not have on or about their person a mobile phone or similar apparatus while in the said vehicle, except when it is parked".
The regulations define "mobile phone" as "any device which is being used directly by a person for the purpose of communications by way of mobile and personal communications systems".
However, drivers who carry a switched-off mobile phone in their pockets do not commit an offence. The ban does not include fixed hand-free units in cars, but it does cover a portable hands-free unit with an earpiece.
Asked about a motorist turning off a phone immediately on being spotted by a garda and then claiming the telephone was not in use, a Department of the Environment spokesman said: "A garda will have formed an impression that the motorist had been using their mobile phone. In the event the garda could go and check the telephone records."
A garda may not search a driver for the possession of a mobile phone. This power exists only where a garda has evidence to suspect that a person is in possession of proscribed drugs or an offensive weapon.
At present, according to Mr Molloy, the offence would not result in an on-the-spot fine but a person may be prosecuted through the courts.
The maximum penalties which a court may impose are €190 for a first offence; €435 for a second offence; €435 and or three months in jail for a third offence.
The ban on using mobile phones while driving will be included in the Road Traffic Bill, with an on-the-spot fine, and it will also attract penalty points which could lead to a driving disqualification.
The Bill is expected to go through the Dáil before Easter.