British supermarket chain Sainsbury's hiked its profits outlook on Wednesday after logging record sales over the Christmas holiday period.

Total sales grew 1.2 percent in the group's third quarter -- or 15 weeks to January 6 -- compared with a year earlier, Sainsbury's said in a trading update.

The London-listed company also expects to achieve further cost-savings from its 2016 acquisition of catalogue chain Argos.

Sainsbury's added that full-year underlying profit before tax was now expected to be "moderately ahead" of expectations.

Analysts had predicted underlying earnings of £559 million ($757 million, 634 million euros), according to consensus forecasts published last week.

"We're pleased with our performance across the group this quarter," said Chief Executive Mike Coupe.

"We had a strong Christmas week, with record sales, over 340,000 online grocery orders and stellar growth in Argos fast-track delivery and collection. "

Online sales meanwhile accounted for one fifth of the group's total sales during the period