US discount retailer Family Dollar Stores Inc says it intends to open up to 500 stores next year after reporting record fourth quarter and full-year sales and earnings.

The expansion is part of measures to drive sales and profitability in fiscal 2012.

"We plan to open 450-500 new stores, a more than 50% increase over fiscal 2011 openings," said chairman and CEO Howard Levine. "We also intend to renovate, relocate or expand over 1,000 stores."

The retailer outlined its goals as it posted an 8.0% rise in profit for the quarter to 27 August to $79.8m or $0.66 per share, compared with $74.0m or $0.56 per share in the same period last year.

Net sales climbed 9.1% to $2.13bn, up from $1.96bn a year ago. Comparable stores sales were up 5.6%, thanks to increased customer traffic and higher average transaction values.

For the full year, net income rose 8.5% to $388.4m or $3.12 per share, up from $358.1m or $2.62 per share, the year before. Annual sales increased 8.7% to $8.55bn from $7.87bn, and comparable store sales rose 5.5%.

Look ahead the retailer, which has more than 7,000 stores, expects full-year earnings of $3.50 to $3.75 per share, with sales up by 8%-10%.