DISPOSABLE income for families in the north is being squeezed by inflation, the Asda's Income Tracker says.
Reduction in spending power is also being driven by rising fuel prices, with household disposable income remaining static at £105 a week.
This is just over half of the figure in the rest of UK, where families continue to enjoy an average weekly disposable income of £202 a week.
Despite the figures for Northern Ireland being up £7 a week on the same period last year, factors such as rising oil prices, higher inflation and a weakened pound have slowed the annual pace of growth to 7.9 per cent.
Year-on-year, a10 per cent hike in the price of fuel has also affected the north’s car-dependent households, who spend an average of £28.90 a week on petrol – compared to the UK average of £19.90.
On a UK-wide basis, the rise in inflation to 1.6 per cent put more pressure on families' spending power but this was cushioned by an equivalent increase in net income.
Up 2.3 per cent year-on-year, a family’s net pay meant an increase in the price of essential items did not affect disposable income by as much.
In the three months to November, regular earnings growth was up 2.7 per cent and unemployment remained steady at 4.8 per cent, while a good performance in the labour market meant employees had better bargaining power for pay.
Food prices in December remained lower by 1.1 per cent year-on-year, however, month-on-month food prices saw an 0.8 per cent increase compared to November and customers checked out of restaurants and hotels with heftier bills.
Against this, there was some relief for households as electricity and gas prices eased compared to those at the end of 2015 and low interest rates also helped keep mortgage interest payments down.
Overall, London remained at the top of the spending power list, with £275 of discretionary income in December – £73 more than the UK average – with Northern Ireland the lowest of all the regions.
