According to new legal docs, obtained by TMZ, Kroy says his estranged wife's been selling off her expansive collection of designer purses, shoes and clothes ... but he says it's unclear what she's doing with the profits and whether any of the stuff being sold is marital property, as opposed to her separate stuff.

Kroy is confident in one thing ... he claims none of the money is going to support their marital estate, which he says is "weighed down by significant debt."

In the docs, Kroy estimates Kim's designer collection is worth hundreds of thousands of dollars ... and he believes she acquired most of it while they were married.

Kroy says he and Kim are in a "dire financial situation" -- including the $1.1 million debt they owe to the IRS -- and he wants the court to identify and equitably divide their marital assets, including their Georgia mansion and personal property.

However, sources close to Kim tell TMZ ... she's selling designer gear she acquired before they were married and used some of the money to buy their kids Christmas presents.

Our sources also say Kim has for years paid house expenses and bills solo.

Remember, Kim and Kroy got a lot going on right now -- as they navigate their divorce, their debts continue to mount ... and they're also trying to unload their massive GA mansion.