Businesses opposed to any congestion charge in Manchester have called for a referendum on the issue.
The Government is due to announce backing for a scheme in Greater Manchester, where drivers would pay up to £5 to enter the city centre at busy times.
There would be two zones - one for driving into the city centre and one for driving through the outer M60 ring road.
The scheme is backed by Manchester City Council and a number of other local councils in the Association of Greater Manchester Authorities (AGMA).
They have put in a £3.5 billion bid to the Government for taxpayers' cash enabling them to set up the charging scheme, with the cash ploughed into improving bus and tram services.
Proponents say the road charge and public transport improvements will lessen traffic congestion - which it is claimed will improve the local economy in the long run.
Opponents, including many major local employers, say it would effectively be the world's biggest congestion charging zone, hit business and local people - and have now called for a public vote.
Local firms Kellogg's, Unilever and property developer Peel Holdings are members of the Greater Manchester Momentum Group (GMMG), formed to fight the scheme.
Manchester Blackley's Labour MP Graham Stringer predicted a backlash at the polls from disgruntled motorists in marginal seats on the fringes of the conurbation.
The Conservative leader of Trafford Council Susan Williams, who is hoping to unseat Transport Secretary Ruth Kelly from the marginal Bolton West seat in the upcoming General Election, said the scheme was "political suicide" for Labour.
