SEATTLE, United States — Amazon.com Inc.'s expansion into private-label activewear is beginning to show up on its website, a move that will generate fresh competition for Nike Inc. and Lululemon Athletica Inc.

Amazon is now selling at least two new product lines — Rebel Canyon and Peak Velocity — that appear to be internal brands, according to analysis by business-intelligence firm L2 Inc.

The e-commerce giant is adding the apparel as part of an effort to fill gaps in its lineup, rather than counting on big sports brands to offer their merchandise on Amazon, according to L2 analyst Cooper Smith.

“Amazon isn’t going to wait for brands to sell on its site, they’re going to make their own private label,” Smith, who handles Amazon research at L2, said in an interview. The names were trademarked by the office of James Struthers, an intellectual-property lawyer who has been associated with earlier Amazon applications, Smith said.

Amazon, based in Seattle, didn’t immediately respond to a request for comment.

Rebel Canyon features men’s sweatpants, sweatshirts and shorts — often priced below $30. The lineup is described on Amazon as “a way of life” and “style you’ll wear on the reg.” The brand also includes some women’s lounge clothing.

Peak Velocity, meanwhile, has higher-end fare, such as a $79 hooded fleece jacket and $59 jogger pants. The descriptions highlight the clothing’s technical features, including moisture wicking and breathability.

The brands have customer reviews dating back to late July, but many of them are from October. Many of the reviews are labelled Amazon Vine, which provides free products to reviewers selected by Amazon — often before the items are widely released.

By Lindsey Rupp, with assistance from Spencer Soper; editors: Nick Turner and Lisa Wolfson.