Motorists could face having to pay on-the-spot fines of up to £5,000 for driving too close to cyclists if new plans being considered by the Government get the go-ahead.
Under the legislation, drivers would be required to leave a distance of at least one metre between their car and a cyclist.
But the RAC has raised doubts over the proposal, calling it “unworkable and unenforceable”.
Currently, the Highway Code states that motorists allow “plenty of room” when overtaking cyclists.
Australia put similar guidelines in place in October last year, requiring drivers to leave 1.5 metres between cyclists when passing them at high speed.
And transport minister Robert Goodwill said the Government was “interested” in following suit and implementing similar measures.
But David Bizley, RAC chief engineer, said the dwindling number of road traffic police officers meant the plan would be difficult to carry out in practice, adding that cycle lanes may provide a better solution.
He said: “Many motorists are also cyclists, and are all too aware of their responsibilities whether on two wheels or four. The question is whether Government resources would be better allocated to running road safety campaigns that educate all road users about how to use shared road space safely and responsibly.
“Where possible, we are in favour of physical segregation between cyclists and motorists in the form of cycle lanes, based on local demand for cycling and where collision risks are high, in order to best ensure cyclists’ safety.”
Figures released by the Government last year showed there had been a rise in fatalities among vulnerable road users such as cyclists, increasing from 46% of all road deaths from 2005 to 209 to 50% last year.
Separate statistics put together by the Department for Transport indicated that cyclists are 17 times more likely to be killed on the road than those travelling in vehicles.
Providing a written response to a parliamentary question, Mr Goodwill said it was unclear how successful the measures introduced in Australia had been.
He said: “There is limited information available regarding the impacts both positive and negative following this change in the law.
“As with other changes of this type introduced overseas, we remain interested in the change and are keeping it under review.”