New Zealand-based outdoor wear company Icebreaker has collaborated with fit specialist Alvanon to develop a new fit and grading system for its garments.

The company, which manufactures merino underwear, mid-layer garments, outerwear and socks for the outdoors, technical sports and lifestyle sectors hired Alvanon to provide it with the latest global fit data to update the fit of its performance and lifestyle clothing.

The three new fits - slim, regular and relaxed, depending on the style and intended use - are designed for comfortable, low-bulk layering, said Icebreaker creative director Rob Achten.

"Our base layers, first layers, mid layers and outer layers are designed to layer together like a single garment - without any seam chafing or zip stacking," he said.

After creating new size charts and fit blocks, Icebreaker tested its new fit system by recruiting a group of women who all considered themselves a size medium but were actually of different shapes, proportions and body types. The test confirmed that the new garment proportions suited a wider variety of women.

The grading - the variation of fit between sizes - was also increased to capture more customers in the full spectrum of sizes.

The new system will be introduced for all garments in Icebreaker's 2013 autumn/winter collection.