The estate of Anna Nicole Smith has failed in its final bid to obtain her late husband's money, seven years after the death of the Playboy model and reality TV star.

A federal judge rejected the effort to obtain about 44 million dollars from the estate of Texas billionaire J Howard Marshall, whom Anna Nicole married in 1994 when he was 89 and she was 26. The oil tycoon died the next year and his will left his 1.6 billion dollar estate to his son and nothing to his famous wife.

Anna Nicole, under her real name of Vickie Lynn Marshall, challenged the will, claiming that her husband promised to leave her more than 300 million dollars on top of the cash and gifts showered on her during their 14-month marriage. A Houston jury said Marshall was mentally fit and under no undue pressure when he wrote the will.

Over the course of nearly 20 years, the Texas bankruptcy court and local and federal courts, including the US Supreme Court, all rejected Anna Nicole's various attempts to overturn Marshall's will and trust and to obtain money from his estate.

The efforts continued even after the model died of an accidental drug overdose in February 2007.

US District Court Judge David O Carter has now denied a request from Smith's estate to sanction the estate of Marshall's son, E Pierce Marshall.

"Time spent litigating the relationship between Vickie Lynn and J Howard has extended for nearly five times the length of their relationship and nearly 20 times the length of their marriage. It is neither reasonable nor practical to go forward," the judge said in his ruling. He noted that it was the last surviving piece of decades of litigation.

"The American taxpayer has supported the burden of this litigation for many years, and it is time for this suit to no longer 'drag its weary length before the Court'," Carter concluded, quoting a Supreme Court decision in the case that itself quoted Charles Dickens' Bleak House.

G Eric Brunstad Jr, lawyer for the Marshall family, said in a statement that the family agreed with the judge that it was time to stop the litigation.