Home Retail Group, which also owns Homebase, said Argos like-for-like sales were 5.8 per cent lower in the second quarter of its financial year, covering the 13 weeks to August 30th.
That compares with the flat performance seen in the previous quarter.
Chief executive Terry Duddy said: "The performance of Argos and Homebase in the latest quarter was reflective of a difficult consumer environment.
"However, the group's focus on cost control should result in benchmark profit for the half-year being in line with our expectations; the group has also had further good cash generation.
"Profits for the financial year as a whole are, as ever, dependent on the key Christmas trading period, though the group's operating model and financial strength will see us well positioned to compete in challenging conditions."
Sales at Argos declined by 1.6 per cent to £927m in the second quarter of the financial year. The company opened nine new stores in this period, taking the portfolio to 718, up from 685 stores a year earlier.