Its survey largest union in the country, of more than 50,000 members reveals that disposable incomes have dropped by an average of £150-a-month - 20% - since April last year.
Unite's General Secretary, Len McCluskey said: "Unite has commissioned polling of more than 50,000 Unite members which shows the average worker has already lost about £150-a-month in disposable income because of the coalition's policies on tax, pay freezes and the soaring cost of household bills.
"Money, so vital for keeping the shopping centres and High Street alive economically, is being drained from peoples' wallets and purses.
"The continuing failure by the Chancellor to realise the error of his ways and wean himself off his austerity addiction has meant that Britain still faces the prospect of a recession and a 1980's scale of joblessness for years to come.
"Last week's appalling jobless figures - a 17-year high - mean that the Budget should be geared at getting people back to work - and in the case of young people, into work for the first time.
"George Osborne's idea of fairness is making the wealthier even richer by cutting the 50p income tax rate. Fairness for those out of work or on low to middle incomes is an alien concept for a Chancellor whose instinct is to protect the rich.
"Pandering to the rich won't help the lost generation of young people into employment.
"Tomorrow's budget should be about putting money in ordinary people's pockets and reversing the damage that has been wrought over the last two years."
Unite's has called the Government to "stop the cuts", and introduce short term tax cuts should to stimulate spending, including a cut in VAT and tax cuts for low and middle income groups and close the tax loopholes that allow the very rich to avoid and/or evade paying their fair share (estimated by Tax Justice Network at £95 billion a year).
It is also pushing for a 'Robin Hood' tax on all city financial transactions (a tax of 0.05% could raise £20 billion a year) needs to introduced, along with minimum tax rates of 40% and 50% on incomes above £100,000 and £150,000 respectively (raising £14.9 billion).
