Transport Secretary Ruth Kelly has denied claims local authorities in England are being "blackmailed" into introducing road pricing schemes.
The government says schemes could tackle rising congestion
Ms Kelly was told by MPs of three areas - Tyne and Wear, Northamptonshire and Manchester - where councils felt they were being pressured into signing up.
The MPs suggested vital cash for new roads was being held back.
Ms Kelly said that was not the intended effect of the government's transport innovation fund.
Ten local authorities have expressed an interest in developing smaller-scale charging systems in their areas, which could be up and running within five years.
Ms Kelly said she expected the first bids to be submitted shortly - but denied councils were being pushed towards road pricing.
"I don't think that areas are being blackmailed into having road pricing.
"If local authorities want to come out with road pricing they need to have the confidence that local transport has improved in that area."
She said road pricing should not be introduced without extensive local consultation.
She hit back at claims London mayor Ken Livingstone ignored the views of local people when he decided to extend the congestion charge zone, saying he had a "strong democratic mandate" for the move.
Committee member David Clelland, Labour MP for Tyne Bridge, said the Tyne and Wear area had been told by the Highways Agency that a bypass improvement would not go ahead unless a demand-management scheme was introduced.
Kettering Tory MP Philip Hollobone said it seemed unlikely Northamptonshire would get road schemes unless some sort of road pricing was brought in.
And Graham Stringer, Labour MP for Manchester Blackley, said the head of Greater Manchester passenger transport authority felt his area was being blackmailed into bringing in road pricing.
Ms Kelly said that she would be very happy to look into the case raised by Mr Clelland.
She said she wanted to "explore whether there was potential for national road pricing" as traffic was set to increase by 30%, according to the recent Eddington report.
"We face quite a stark choice between either introducing road pricing and investing very, very significantly in our road infrastructure," she told the committee.
But she denied the Local Transport Bill, which gives councils more control over road pricing schemes and ensures they are compatible with schemes in other areas, was designed to pave the way for a national scheme.
A petition against road pricing on the Downing Street website received nearly two million online signatories.