Struggling UK supermarket group J Sainsbury has reported total third-quarter sales growth of 6.1%, and said sales trends over the Christmas period were encouraging.

Sales growth excluding petrol was 2.7% for the 12 weeks to 1 January. Like-for-like sales were up 2.4%; however, excluding petrol, like-for-like sales were down 1.2% on the year-ago period.

For the four weeks to 1 January, including the crucial Christmas period, like-for-like sales rose 2.5%, but slid 0.4% excluding petrol sales.

"After a difficult November, there was an improving trend over the Christmas and New Year period, which is encouraging given the tougher comparatives for the same period last year. This sales performance was in line with our plans and was a good first step in delivering our sales led recovery," said chief executive Justin King.

Sainsbury's has been struggling with supply chain problems but King said the company was pleased with the levels of availability and customer service achieved over the Christmas period.

"We are committed to making continuous improvements to our operations and have put a number of actions in place to ensure progress, particularly around product availability and store labour. Our customers are starting to see the benefit," he added.

King also warned that the third quarter's competitive market conditions would continue into the fourth quarter, with renewed pricing activity.