Michael Jackson was not present in court to hear the judge's decision

Nona Jackson, 36, from London, asked for joint custody of Prince Michael, 10, Paris, 9, and Prince Michael II.

But Los Angeles Judge Robert A Schnider said the evidence provided failed to "establish any genetic relationship".

Mr Jackson settled a custody row with his ex-wife, Debbie Rowe, over his two eldest children in September last year.

Details of the settlement have not been released.

Child support

Ms Rowe agreed to give up her parental rights in 2001 following the collapse of their three year marriage, but went to court in 2004 to reverse the decision.

The singer has not identified the mother of his youngest child, 5-year-old Prince Michael II.

"Debbie's hospital records will prove that my kids are not hers because of DNA," Nona Jackson, speaking via telephone and loudspeaker, told the court on Wednesday.

Michael Jackson and Debbie Rowe settled their custody row last year

Superior Court Judge Schnider also denied Ms Jackson's request to annul the singer's marriages to Ms Rowe and Lisa Marie Presley, both of which ended in divorce.

Nona Jackson's other requests to the court included a petition for child support, along with possession of Mr Jackson's Neverland Ranch and a San Fernando Valley home.

Mr Jackson and Ms Rowe were not present.

In court papers Nona Jackson claimed her and the US singer were "a sexually active couple", adding that she had written more than 3,000 songs for him.

Ms Jackson's three previous attempts to join in the custody battle were rejected by the same judge in November 2006 and in February and May this year, on the grounds she had failed to notify either Mr Jackson or Ms Rowe of the hearings.