Athletic footwear group K-Swiss Inc has posted a 59.5 per cent leap in first quarter net earnings to $21.76 million, up from $13.64m in the same period a year earlier.

The California-based company, which produces footwear under the K-Swiss and Royal Elastics brands, also reported total worldwide revenues of $152.02m for the quarter, a 31 per cent year-on-year increase on the previous first quarter.

"European operations have shown marked improvement by reaching profitability in the first quarter and posting sizable increases in backlog, while Asia is starting to show signs of renewed life with a strong backlog and a new Japanese distributor," president Steven Nichols said.

"With over $90m of cash on our balance sheet, we will also continue to invest in these opportunities, the Royal Elastics brand and in our own stock."

K-Swiss said it expected revenue of up to $117m for the second quarter.