She has worn some memorable outfits over the years, and now fashion designer Victoria Beckham is putting more than 600 items from her extensive wardrobe up for sale to raise money for a charity to help mothers living with HIV.

The former Spice Girl, who has four children, said a trip to meet some of the women involved in the work of Mentor Mothers - educating women with HIV about access to treatment and fighting the stigma of the diagnosis in Africa - inspired her to take action.

Beckham said she has kept some important and sentimental pieces from her wardrobe for her three-year-old daughter Harper, but added that she was more focused on fundraising.

"I'm keeping a few pieces (for Harper) but for me it was more important to raise money for this charity," she said in a video on the charity's website.

"As a woman we have a responsibility to really help and support other women, to do what we can do to help and I'd like to thank everybody at Outnet for joining me on this journey."

Choosing items for the sale on August 20 was an enjoyable experience, Beckham said.

"E very single piece that I have put in to be sold brought back a lot of memories, a lot of really, really happy memories of myself and David, of myself and the children, of different events that I've been to and a lot of these pieces have been made specially for me by the designers."

The charity, which will use proceeds from the sale on to help fund education around preventing the transmission of aids from mother to child, said it is grateful for Beckham's "incredible support and generosity ".