Pressing ahead with an expansion of road tolls would be "electoral suicide" for the Government, a motoring campaigner said.
A Whitehall feasibility study of new ownership and financing models for the network, ordered by Prime Minister David Cameron, is due to report in the New Year.
Reports suggest reforms - including allowing private firms to charge motorists to use new major roads - will feature among proposals in the Government's mid-term review.
Deputy Prime Minister Nick Clegg has said there will be a number of "important new steps" in the document, which is also due to be published early in 2013.
The Department for Transport insisted that it was not considering breaching a commitment to restrict tolls to new major roads or those upgraded "beyond all recognition".
Peter Roberts of the Alliance of British Drivers said there would be a massive backlash from voters - pointing to his 2007 petition against nationwide road pricing which attracted 1.3 million signatures.
"I think people have made their views on road tolling, road pricing, very very clear. I think it would be electoral suicide...kind of like the poll tax on wheels," he told BBC Radio 4's Today.
"Most drivers already believe they are paying too much for the roads."
But Stephen Glaister of the RAC Foundation suggested drivers could accept a package that saw tolls imposed in return for reductions in fuel duty and road tax, with the funds devoted to improvements.
In March, Mr Cameron ordered an urgent Treasury study of new models "for getting large-scale private investment into the national roads network".
But he insisted it did not mean a return to the proposals for "mass tolling" under Labour which sparked the huge petition response on the Downing Street website.
A DfT spokesman said: "The Government has made a clear commitment not to toll existing road capacity and this has not changed. We have always said we would look at schemes which would fund significant new capacity through tolling. This would be in very limited circumstances and only where schemes deliver new roads or transform an existing road literally beyond all recognition."