Wools of New Zealand chief executive Rosstan Mazey said the wool was in the 28-31 micron range, which was more traditionally used in the production of interior textiles.
"It's a big step for crossbred wool and it's tremendously exciting to see our wool moving into high-end attire,'' Mr Mazey said.
Mr McCall, who farms at Winton with wife Jan and their daughter Sheena, hoped such an initiative might help to build momentum and raise prices.
Having been farming all his life and with a passion for wool, he always had faith the fibre was "going to come back''.
But he started to lose some of that positivity a few years ago and says it is going to take a bit to lift it to where it needed to be.
However, it was good to see there were alternatives for crossbred wool other than
carpet, he said.
Steven Parsons, brand and business development manager for Wools of New Zealand in the UK, said the RWS was imagined and developed as the global standard for growing wool in 2016.
"Wools of New Zealand have joined a rapidly growing number of international brands and the Textile Exchange as strong advocates for RWS as a global wool production standard, providing an assurance to consumers that the wool they are buying has been grown to the highest possible standards across farm management and animal welfare.
"M&S represent a powerful partner in that respect, as they are able to influence the value chain and change attitudes towards fibre production.
"There is a new reality out there for both producers and retailers and that is they need to be responsible for driving supply chains towards true sustainability,'' Mr Parsons said.
Mr Mazey said their 14 grower shareholders were accredited under the RWS throughout New Zealand.
The launch of the new product was expected to boost interest in both WNZ's wool and RWS credentials and it was expected more growers would become RWS-certified as market demand built.
Rabobank's latest Agribusiness Monthly said New Zealand had a disappointing month in August. The volume shipped to China was the lowest since August 2016.
Textiles had largely been left out of the trade war to date but were implicated in the latest round of tariffs implemented by the US.
Semi-processed wool products such as wool yarn and fabric, as well as wool carpets, imported from China would attract a 10% tariff. China was the second-largest supplier of wool carpets to the US behind India.
The market for coarse crossbred wool rose slightly through the month before finishing September about where it started, with the NZWSI coarse crossbred indicator at 330c/kg clean. Clearance rates at auction also fell towards the end of the month.
Beef + Lamb New Zealand's new season outlook for 2018-19 estimated a 4.3% lift in the forecast value of all wool for the season. That comprised gains in crossbred, lambswool and medium wool and a fall in the value of fine wool. Wool production in New Zealand was forecast to fall 2.2%, reflecting lower fleece weights and fewer sheep shorn.
Fine wool prices continued to reflect the relative strength of the Australian market. Although prices softened 4% through September, reduced supply remained a critical factor for the price outlook.
