Leading apparel retailer Gap Inc has posted a 54 per cent leap in first quarter net earnings to $312 million, up from $202m in the same period last year.

The San Francisco-based company also reported a nine per cent rise in quarterly sales to $3.7 billion, up from $3.4bn in the previous first quarter, and seven per cent same-store sales growth.

"Strong product acceptance at Gap, Old Navy and Banana Republic and tight inventory management drove record earnings for our shareholders in the first quarter," CEO Paul Pressler said.

"We're pleased with our continued progress in better serving customers in our existing business as we build a foundation for longer-term growth."

Comparable store sales growth was highest in the company's Banana Republic division, with sales at stores open at least a year rising 21 per cent during the quarter.