Papers filed at the High Court say Naomi Parry and Catriona Gourlay sent “various items of personal property owned by Amy during her lifetime” to two auctions – in 2021 and this year.
By putting the items up for sale “in their own names and on their own behalf”, the papers said, the women “converted” the late performer’s property “to their own use”.
A statement first issued by a spokesperson for the Amy Winehouse Estate last month said: “In 2021, Amy’s estate auctioned items from her life and career, with 30% of the proceeds going to the Amy Winehouse Foundation.
“Two individuals sold a number of items at that auction and have retained the proceeds: the items were all Amy-related.
“This year they have put more Amy-related items up for auction and together the two auctions have generated six-figure sums for each of them.
“The estate has questioned how these items came into their possession and has not had satisfactory answers.
“The estate has therefore launched a legal process to clarify the situation. The Amy Winehouse Foundation will directly benefit if monies are recovered from either defendant.”
Ms Winehouse died in 2011, aged 27.
After two inquests, her cause of death was revealed to be accidental by way of alcohol poisoning.
Her 2006 album Back To Black made her an international star and won five Grammys, including record of the year and song of the year for Rehab.