A judge's ruling that Michael Jackson's mother can challenge the administrators of her son's estate could result in a deal that will determine control of the singer's gargantuan assets, a lawyer for Katherine Jackson said yesterday.

Los Angeles superior court judge Mitchell Beckloff said Michael Jackson's mother could argue against keeping the men currently administering her son's estate without being disinherited.

Katherine Jackson had sought a favourable ruling from Beckloff that she could contest the authority of attorney John Branca and music executive John McClain to guide the pop singer's fortune. The men were named executors of the estate, which could be worth more than $500 million, in Michael Jackson's 2002 will.

Beckloff's ruling clears the way for more arguments and possibly a hearing on whether the men were best suited to control Jackson's considerable estate. The pair have already brokered deals for a film, books, museum show and various memorabilia that are expected to generate tens of millions of dollars.

Katherine Jackson's legal team, however, has sought to challenge one or both of the men's authority. A key roadblock was whether a challenge would be deemed a contest to Michael Jackson's will. A provision of the singer's private trust, which calls for his mother to receive 40%, calls for anyone who challenges the will to be disinherited.