"Vivienne Westwood: The Personal Collection" comprises more than 250 clothing and accessory items, most of which were runway looks before being worn by the designer herself.
The collection features some of her most iconic designs, including corsets, tartan patterns, billowing taffeta gowns, platform heels and T-shirts bearing political slogans.
The online sale hosted by Christie's in London and will include a live auction.
The lots include custom-designed playing card prints intended to shed light on issues such as climate change, social inequality and human rights.
Ten have been enlarged and signed by Westwood, who died in 2022 aged 81, to raise funds for Greenpeace.
Other proceeds will be donated to charities including Amnesty International, Doctors Without Borders (MSF) and the designer's own Vivienne Foundation, which works with NGOs "to create a better society and halt climate change".
The collection's cataloguer and sale coordinator, Clementine Swallow, told AFP that "Vivienne's Playing Cards" were the catalyst for a larger charity auction.
Although Westwood "knew she wasn't going to be able to see the project out... she had the wish that her personal wardrobe would be sold to benefit other charities important to her", Swallow said.
Westwood's widower Andreas Kronthaler, 58, has been closely involved in the sale. "He's personally put together each of the lots to be an outfit she would have worn," Swallow said.
"These are the items that she chose to have, of the many thousand things that she designed over 40 years," she said. "They are the kinds of things that she felt were the epitome of her designs."
- Sustainability -
The collection includes a number of pieces that illustrate Westwood's cultural impact, and the wide range of influences she drew from in her four-decade career.
The earliest piece is a 1983 navy jacket-and-skirt ensemble from the "World's End, Witches" Autumn-Winter 1983 collection, when Westwood was still in collaboration with her first husband and manager of the Sex Pistols, Malcolm McLaren.
Westwood was influenced by British history but gave classic designs a provocative edge, Swallow said, noting in particular a taffeta ball gown with "bondage-style black wrappings".
Many of the clothes feature political graphics and slogans that reflected Westwood's advocacy of social justice.
"A big part of Vivienne's identity is activism... She really is one of those designers who took their clothes and used them as a mouthpiece to voice her ideas and political opinions," Swallow said.
Other collection highlights include Westwood's signature pink tartan pattern and a cropped blue jacket identical to the one worn by supermodel Naomi Campbell during a notorious incident when she fell on the catwalk while wearing 12-inch (30-centimetre) Westwood platforms.
There are also early examples of the designer's elasticated corsets.
Sustainability and ethical fashion are also key themes -- The most expensive piece is a cut-out illusion gown hand stitched with intricate beading and gold panelling, created with artisans and craftspeople in Kenya.
All materials used in the exhibition are recycled or recyclable, including cardboard signage and plywood stands.
"It's been a great lesson for us, (proving that) we can do recyclable exhibitions," Swallow said.
Collection items are listed at £200 to £7,000 ($255 to $9,000) but are expected to fetch much more given Westwood's reputation.
Museums and other institutions are expected to bid but Swallow said the designer "loved the idea that (her clothes) might be worn by real people".
"The idea that they might have another life is wonderful," she said.
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© Agence France-Presse