It is unclear if Rainey Kelly Campbell Roalfe/Y&R, which handles the core £26 million M&S account, has been asked to pitch ideas for the launch.
The brief is calling for a strategic plan on how best to position the range against its competitors as well as the most effective brand name for the collection.
The UK clothes market is the biggest retail sector after food and groceries.
The campaign will attempt to lure the all-important 35- to 45-year-old women into M&S shops.
Analysts have predicted a slump in the womenswear market on the back of older consumers growing increasingly concerned about the falling value of savings and pensions. Womenswear sales represented 52 per cent of the £30.4 billion clothing market last year.
The retail consultancy Verdict predicts that growth in the womenswear market will slump to 3.2 per cent this year, compared with 6.8 per cent last year.
In January this year, M&S ended its eight-month search for a marketing chief with the appointment of Alice Avis, a former global brand director of Johnnie Walker whisky. She joined as the director of marketing and e-commerce, reporting to the company's chief executive, Roger Holmes.
M&S denied there was a review and RKCR/Y&R was unavailable for comment as Campaign went to press.