Lindsay Lohan's father has begged a judge to order her to rehab.

Michael Lohan - who has repeatedly claimed the actress is addicted to prescription drugs - had his lawyer Lisa Bloom write a letter to the official presiding over her driving over the influence (DUI) probation case asking for more steps to be taken to intervene in his daughter's life.

The note read: "It is clear to Michael that the current court-ordered condition of her probation - namely, that she is required only to attend alcohol education classes - is insufficient."

The letter goes on to ask that the judge "order Lindsay into an inpatient residential drug and alcohol treatment program".

In the document, obtained by gossip website TMZ, it is suggested the 'Mean Girls' star could receive treatment at New York facility Cold Spring Hills, adding: "Her family could easily attend family therapy with her as needed."

Michael acknowledges the 23-year-old star may not be sent to rehab, so has also suggested an alternative intervention plan.

The letter explains: "Michael respectfully requests the Court order Lindsay to be subject to frequent, random, court ordered drug testing; that Lindsay be subjected to random searches of her home and person by law enforcement; and that Lindsay's probation be extended for an additional term of years to continue her period of court supervision."

According to the document, Michael is asking for legal help because he is so concerned the actress' alleged drug habit will kill her in the way other celebrities have died.

It concludes: "It is painful for a father to ask a court for stricter controls on his own beloved daughter, but the alternative - that Lindsay becomes the next Hollywood statistic, the next Heath Ledger, Michael Jackson or Anna Nicole Smith - is far worse."

Lindsay was sentenced to three years probation in August 2007 after pleading guilty to cocaine use and DUI.