A database designed to form the basis of the council tax revaluation will be used for stealth hikes in other taxes, the Conservatives have warned.
Revaluation could lead to increased bills for many people
Details on the system will also be used to assess liability for capital gains and inheritance tax, said shadow local government secretary Caroline Spelman.
Revaluation has been postponed until about 2010 but the Valuation Office Agency is continuing to value homes.
The agency says it is not working by stealth, nor have its methods changed.
The Tories called for valuation officers' powers allowing them to enter people's homes or face a £500 fine to be scrapped.
The revaluation of 22 million English homes for council tax is likely to now happen in 2010 after being postponed from 2007.
At present, information on two million homes is on the database and, in answer to a series of parliamentary questions, it emerged that it will be available to the Inland Revenue for calculating capital gains and inheritance tax as well.
"Day by day it is becoming clear that whilst Labour may claim to have postponed revaluation, it is actually well under way by stealth," said Ms Spelman.
"The American computer database is being rolled out across the country with the details of every home logged."
She described how "clipboard-wielding inspectors" will be recording significant features of homes including number of bedrooms, large gardens and nice views.
"This will be used to hike up council tax bills and also to increase inheritance tax and capital gains by stealth," she said.
Inspectors have been equipped with 2,126 digital cameras, costing £438,749.
Householders who refuse to let them in could be fined £500 and receive a criminal record.
In the written reply, Home Office minister Hazel Blears said: "A person who intentionally obstructs a valuation officer commits an offence and may be liable to a fine not exceeding level two (£500) on the standard scale."
Ms Spelman told the Sunday Telegraph: "Although Conservatives cannot condone people breaking the law, fining them £500 and giving them a criminal record if they don't co-operate is outrageous.
"The Valuation Office Agency's powers to enter people's homes should be abolished."
But Andrew Hudson, chief executive of the Valuation Office Agency, said fines for those obstructing valuation officers were not new - they had been in place since the council tax was first introduced in 1993.
He said internal inspections of home were rare and argued that it was in owners' own interest to allow entry to ensure the correct tax band was used.
Mr Hudson said his agency's duty was to ensure every home in England and Wales was in the correct council tax band, whether there was a revaluation or not.
He said details of the agency's work had been announced by local government minister Phil Woolas in the House of Commons.
"So we do not see ourselves as working 'by stealth'," he said.
Price of a view?
Mr Hudson said the way the agency valued property had not changed either.
"Scenic views" had a bearing on council tax bands only if they affected the overall value of the property - as had always been the case, he said.
Every home in Wales was revalued last year, with a third moving up at least one valuation band and 8% moving down.
But it has been 14 years since the last valuation in England and property prices have risen sharply since, particularly in London and the South East.