LOS ANGELES — Koos Van den Akker is everywhere these days.

With the hallmark textile collages that he’s crafted since the Seventies now referenced in the spring collections of Balenciaga Le Dix, Marc Jacobs and others, the Dutch-born designer suddenly finds himself in demand. One moment he’s fielding interviews from his Madison Avenue salon; the next he’s heading west to a gallery opening here of a retrospective featuring three decades of his work.

Today, Van den Akker will likely pique public interest further as he sits behind his sewing machine in one of Henri Bendel’s windows, from noon to 3 p.m., giving the world — or at least those passing by — a view of his craft-intensive process.

“He’s really the king of collage,” noted Anna Garner, fashion director at Bendel’s. “He still sits at the sewing machine and creates one-of-a-kind items. His whole creative process is one of the reasons for us wanting to bring him in.”

It’s the start of a big push for Bendel’s, which over the next two months will launch in-store boutiques for Stephen Burrows, Patricia Field and Ana Abdul of Language.

Within 24 hours of Bendel’s first Van den Akker delivery last week, nearly half of its 40-piece order of patchwork peasant blouses and tiered skirts, retail priced at about $498 and $1,098, respectively, sold out. Garner quickly requested more. “Koos will literally be sewing his reorders in the windows,” she laughed.

Sales of vintage Van den Akker have also been “very healthy” at Decades Gallery in Los Angeles since the retrospective opened there Jan. 11. Above the Decades vintage boutique on Melrose Avenue, the 1,500-square-foot gallery space is devoted to the exhibition — and sale — of a brand whose owner-curator Cameron Silver believes is edging onto the fashion radar. (Not all items in the Koos show are available: Blaine Trump declined to part from an A-line tweed suit with circle appliques.) The exhibition closes Feb. 15.

And the fashion elite is embracing Van den Akker even as his popularity grows on the most mass of media, QVC. His Koos of Course! line is among the cable shopping channel’s top sellers, bringing in about $1 million in sales, according to the designer, during his one-hour monthly appearances. Among the hot items, blouses retail for $39.92 and jumpers for $49.50. (The privately owned parent company, Comcast, declines to comment on sales figures, but said Van den Akker could be quoted on the subject.)

“I’ve always loved doing good stuff for the masses,” he said. “I’d love to do home furnishing, but I love sitting behind the machine. My couture is my kitchen, it’s where my ideas come. But this other thing is like vaudeville.”

Meanwhile, last summer, Silver at Decades knew Van den Akker’s time was about to hit when Nicolas Ghesquiere left the store with several pieces.

Silver contacted Van den Akker and proposed the retrospective, then phoned editor friends at Harper’s Bazaar and Vogue, and stories on the designer’s cult-like influence followed. Interestingly, Silver stocked away the vintage Van den Akker on more of a hunch than admiration for the craft-like aesthetic of the patchwork.

He’s since gained a better appreciation. “There are fans coming in who are not necessarily vintage clients, but art clients. They’re interested in the mechanics of how Koos does things.”

Silver has also been fielding requests from designers and merchandisers. At the opening, the local design community turned out in force, from Magda Berliner and Eduardo Lucero to Kevan Hall and Jeremy Scott. “I think we’re still going to see his inspiration next fall,” said Silver.

But expect it on a more mass scale, he said, noting representatives from BCBG, Laundry and other local manufacturers had dropped by in recent weeks.

If imitation is flattery, Van den Akker has learned to accept gracefully the homages. The difference this time, however, is how open everyone is to publicly acknowledging his influence. “It’s like faking your death. You suddenly get all this attention — a retrospective, articles. Then you pop up and say ‘Boo. I’m here!,”‘ he said.

Customers of his hand-made items, he assured, have no problem with QVC ties because they are getting unique pieces. The salon, with its staff of eight besides the designer, accounts for $800,000 in sales. That may change as Van den Akker considers requests from specialty buyers hot to get in on the buzz.

“If ever a company would buy Koos, I would want to stay exactly where I am, the same studio, the same focus on my work with my apron on and my sewing machine,” said the craftsman, who arrived in New York in 1969.

And even as Silver readies a collection of vintage pieces for sale at Barneys in New York during fashion week next month, Van den Akker is pragmatic about his revival.

“It will pass,” he peacefully observed. “But right now I’m enjoying it all.”

Silver believes it will be later rather than sooner. “The Koos moment is not fleeting. It’s going to last for a while longer because he has so many ideas.”