Shares in retailer JB Hi-Fi rose after the company posted a 9.4 per cent fall in first half profit on the back of a challenging post-Christmas period, but said it expected a 5 per cent increase in full-year sales.

Net profit for the six months to December 31 was $79.6 million, down 9.4 per cent from $87.9 million in the previous corresponding period.

Revenue rose 5.5 per cent to $1.77 billion.

Earnings before interest and tax (EBIT) were $120.7 million, down 4.9 per cent from $127.0 million, in line with the company's guidance.

JB Hi-Fi declared a fully-franked interim dividend of 49 cents.

"Assuming trading conditions in the second half of fiscal 2012 are comparable with the first half of FY12, the company expects sales in FY12 to be circa $3.1 billion, a five per cent increase on the prior year," the company said in a statement on Monday.

In December, JB Hi-Fi said it expected earnings before interest and tax (EBIT) for the six months to December 31 would be about five per cent less than the previous corresponding period.

JB shares were up 40 cents, or 3.34 per cent, to $12.39 at 7.45am.

The company said it had experienced soft January sales, with lower-than-anticipated sales in TV panels and weakness in IT accessories and cameras which had been in short supply due to the Thailand floods.

JB Hi-Fi-branded comparable store sales in January were down 5.5 per cent, the company said.

"While still early, we have seen an improvement in February sales which, for the month-to-date for JB Hi-Fi-branded stores grew 8.4 per cent and on a comparable store basis sales grew one per cent,” the company said.

Consequently, in the first six weeks of the second half, sales figures for JB Hi-Fi-branded stores grew 3.3 per cent. But, on a comparable-store basis, sales in the first six weeks were down 3.9 per cent.

Chief executive Terry Smart said it had been a tough start to the year but JB Hi-Fi expected sales to improve.

"In our view, consumers were suffering from promotional fatigue and, therefore, have not reacted as well to our post-Christmas promotional offers as in previous years,” Mr Smart said.

"While the market will remain challenging, we will continue to focus on delivering customers a unique and engaging shopping experience both in store and online."

JB Hi-Fi also said online sales grew 87.7 per over the half-year, while December sales were up 109 per cent.

With an average of 1.4 million visitations per week in December 2011 and 957,000 per week over the first half of 2012, the online site continued to be an “important sales generator for both in store and online sales,” the company said.

The company said it planned to open six JB Hi-Fi stores in the second half of 2012 after having opened 10 stores in the first half.