US department store retailer Macy's is launching 13 new apparel and footwear brands and expanding a further 11 existing ones, as part of a drive to boost its business with customers between the ages of 13 and 30.

The first phase of its so-called Millennial initiative will be rolled out this autumn and next spring, and will include an exclusive Marilyn Monroe fashion collection, a men's T-shirt line from Fatal Clothing, Keds apparel, and a partnership with MADE Fashion Week.

The brands will feature in the retailer's mstylelab and Impulse departments, which target shoppers aged 13-22 and 19-30 respectively. Prices will range from US$23 to $225.

Macy's earlier this year announced an internal restructure to focus on merchandise for the millennial generation - the US's largest and most diverse age demographic with spending estimated at $65bn each year. Consumers in this group are keenly interested in trends, style and value, the retailer says.

"We have identified millennials as a priority customer for Macy's, and we know that growing our relevance for this customer will start with product," said Jeffrey Gennette, Macy's chief merchandising officer.

"This product investment and repositioning is the first phase of our millennial strategy and will help strengthen Macy's credentials and credibility with this customer by offering them newness, fashion and innovation across product categories and lifestyles."

Other new lines planned include a new Truth or Dare shoe collection created by Madonna, Blossom & Clover clothing, G-Star Raw, Ambiguous, Ezekiel Clothing, Comune, DTA, Plan B and Argyleculture.

The department store retailer will also expand its Rachel Rachel Roy, Else, Kensie, DV by Dolce Vita, Material Girl, and American Rag brands to more stores. Items will be available priced from $6-$200.

"Macy's recognised there was a significant area of opportunity within the millennial generation," added Molly Langenstein, Macy's executive vice president and group merchandise manager for millennial.

"In an effort to fill that white space, we used the results of extensive research to better understand the preferences of these customers, go out into the market and plan our assortments."

Last month, the retailer unveiled its limited-edition 'Nicole Richie for Impulse' clothing collection, which includes 1960s and 1970s inspired maxi dresses, studded jackets with faux leather, and printed dresses.