Results of the Census, run by the Office for National Statistics, were revealed four weeks ago. The population of many areas was much lower than the ONS's mid-year estimates, leaving councils in fear of budget cuts.
Councils in areas that have apparently had population falls are concerned they will have funding slashed, as a locality's population affects the grant it receives from central government.
Derby City Council and Westminster City Council are two such authorities leading the public affairs push.
Westminster representatives will meet the ONS on 11 November and will target Ruth Kelly MP, the Treasury minister responsible for the Census, in a letter-writing campaign.
The council has also commissioned pollster MORI to handle what is effectively its own sample mini-census.
'We think the Census figures are wrong. It was a flawed statistics-gathering process in some areas,' said Westminster comms officer Ian Farrow.
The Census had Westminster's population at 181,279, down by more than 25 per cent in comparison with the ONS's own mid-year (2000) estimate.
Derby's population has reportedly fallen by six per cent to around 221,000.
Both Westminster and Derby confirmed that if grants are reduced in line with alleged population falls, services will be cut and/or council tax will have to rise.
The ONS said the Census figures have 'been through a rigorous process of quality assurance'. It admitted its mid-year estimates 'have been over-estimating both the size of, and growth in, the population over the last few years in many areas'.
Other councils lobbying include Manchester City Council, Norwich City Council and Suffolk's Forest Heath District Council.