The Ace collection was launched at Milan's Salone del Mobile furniture fair and is constructed from moulded plywood upholstered in foam. The chairs feature rounded backs, which are flexible to add "a springy feeling". The furniture comes in a range of different seat widths or as a sofa version, which is sold in muted greys, blues and reds.
The seating arrives in pieces that can be assembled "within a few minutes", according to the brand. The back and seat screw together, and the four legs slot into pre-made holes.
Related stories: more flat-pack furniture
"Flat-packed upholstered lounge furniture might sound like a crazy idea," said the company. "For Hans Hornemann it was a requirement that the flat-pack principle did not involve any compromise with the design."
Hornemann apparently based the furniture design on his own life in Copenhagen, and has tailored it for "young urban dwellers" looking for flexible living options – much like Ikea's PS 2014 collection.
Danish design brand Hay appears to be targeting a similar audience. Also in Milan, the company debuted a flat-pack tubular steel sofa designed by the Bouroullec brothers
Hay's founders told Dezeen that Swedish flat-pack furniture giant Ikea is fuelling demand for western lifestyle in China, a huge market for many brands.
Other companies designing flat-pack furniture to rival Ikea include Artifox, which sells quick-assembly wooden desks and bike racks, while Greycork's furniture can apparently be put together in less than four minutes.
Normann Copenhagen also recently responded to the trend for small sofas, expanding its Era sofa collection with a two-seater edition designed by Simon Legald.
The Ace collection was shown at Salone del Mobile from 12 to 17 April 2016.