Supermarket giant Coles has locked in prices on 150 more everyday products to the end of January as another interest rate rise on Tuesday threatens to put the squeeze on low-income households.

“We know it’s been a really tough year for many of our customers and they are looking for prices they can rely on,” Coles chief executive of commercial and express Leah Weckert said.

The Reserve Bank aims to finally throw cold water on consumer spending with what economists are tipping will be a 50 basis point rise in the cash rate, enough “to avoid underwhelming the market at a time of extreme nervousness”, Citi Group analysts said last week.

“The view [on the rate rise] has come from recent global events that include the extremely large amount of fiscal stimulus in the UK and upwardly revised policy rate expectations for major central banks.”

Such a rise would weigh heavily on Australian consumers at a time when retail analysts say shoppers, particularly those earning less than $50,000 a year, are tempering their intentions to spend.

The latest UBS quarterly consumer survey shows while the nation’s wealthiest Australians still have positive sentiments about the economy and are expected to keep spending, lower income earners now have an “outright negative” financial outlook.

“Cost-of-living pressures are forcing consumers to spend more on essentials, with food, fuel, utility and healthcare costs impacting most - this disproportionately hurts lower-income earners,” UBS strategist Richard Schellbach wrote in a note to clients.

“Middle-income earners tend to be still positive on most measures, although with less conviction than was shown in previous surveys this year.”