The report predicts "the worst Christmas for a generation".
UK consumers plan to spend 7% less this Christmas than they did last year, a survey from business advisory group Deloitte has suggested.
Deloitte warned this festive season may be "one of the toughest in decades" for retailers. The expected fall compares with a 7% rise in spending in 2007.
Yet while 24% of UK consumers intend to spend less this Christmas, the report said 57% planned to spend the same.
A further 19% of respondents said they expected to spend more.
A separate poll of parents found that many were planning to cut spending this Christmas, and that one in 10 feared a family's main bread winner would be made redundant within the next six months.
The total average amount spent per adult this year will be £655 on gifts, socialising, and food and drink, the Deloitte survey estimates.
Broadly speaking, we believe sales will be flat this Christmas, with a slight fall possible
While the overall amount spent is set to fall by 7% from last year, it is socialising where the biggest cutbacks are planned - 12% less than last year.
At the same time, more people plan to buy some of their Christmas gifts from supermarkets as they seek lower prices - 56% compared with 52% last year.
"I think the main headline is this is worst Christmas for a generation," said Richard Hyman, strategic advisor to the retail practice at Deloitte.
"But as a nation we'll be spending £36bn so it's not a total disaster.
"Broadly speaking, we believe sales will be flat this Christmas, with a slight fall possible."
Mr Hyman added that retailers will be hopeful that last week's interest rate cut will boost people's disposable incomes.
'Comfortable with debt'
Although only 19% of all adults plan to spend more this year, the percentage among 16 to 24-year-olds rises to 36%.
Perhaps disturbingly, 49% of this age group said they intended to have a good time at Christmas "and worry about the cost later".
"This age group has grown up in an affluent society with technology products and designer wear, are comfortable with debt, and have never been in a recession," said Tarlok Teji, Deloitte's head of retail.
"Their high propensity to spend represents an opportunity for those retailers targeting younger customers."
Deloitte's 14th annual Christmas Retail Survey spoke to 1,000 people across the country.
A separate poll of more than 5,000 parents, published by the Family and Parenting Institute, found one in four said their household income was not enough to pay the bills each month.
Of these, 74% said they would be cutting their Christmas spending to save money.
"Even more of a strain is the pervasive fear that they will be out of work or even lose their home," said chief executive Mary MacLeod.
Some parents said that tax credits were easing the strain on their finances.