Businesses in Kirklees could save millions by appealing over their business rates.
The business rates are based on the rateable value of a company, which was set by a review of property values last carried out in 2007.
Companies can appeal against the value assigned to their property and many successfully do so.
But a report by rates specialist CVS claimed thousands of firms have not appealed, and if they did they could make significant savings.
In Kirklees, CVS estimate there are still 12,459 sites yet to appeal their rateable value, which equates to £153.6m.
CVS claimed successful appeals could save firms a total of £20m across the seven years that the valuation stands.
A majority – 65 per cent – of respondents favoured retaining the predictability of five-yearly revaluations, with just seven per cent supporting annual reassessments.
Revaluations are currently supposed to happen every five years, although the Government postponed the last one, which was due in 2012.
Chief executive of CVS Mark Rigby said: “Any reform must protect the predictability and stability of this significant overhead for ratepayers.
“CVS has been saying this for some time and these research findings clearly show that stability and predictability is what businesses want.
“Increasing the frequency of reassessments could expose businesses to uncertainty in payments, while imposing an unsustainable burden on the Valuation Office Agency.
“The business rates system is not fundamentally broken – the Government should not be pressured into introducing new and unproven methods.
“The focus should be on creating a less adversarial system, which doesn’t leave businesses confused and frustrated about business rates.”
The Treasury recently shelved plans to change the appeals system which many feared would make it more complicated.