Actress Nicole Richie. - Contributed

Bangshowbiz

Nicole Richie's lawyer claims drugs tests used to charge her with DUI (driving under the influence) were falsified.

The star's attorney Shawn Chapman Holley stated in legal documents filed on Tuesday that Nicole's defence team plans to call on drugs expert Dr. Terence McGee as their key witness to challenge the results obtained by police.

Challenge evidence

The papers read: "Dr. Terence McGee, as a defence expert, will challenge the prosecutor's scientific evidence and the conclusions reached by the drug recognition expert."

Nicole was stopped by police after driving the wrong way on a Los Angeles freeway on December 11. She failed a field sobriety test and reportedly admitted to police she had smoked marijuana and taken Vicodin.

Chapman Holley asked Los Angeles Superior Court Commissioner Steven K.

Lubell to delay the trial - due to start today - because McGee would not be available until August 5.

Chapman Holley wrote: "His testimony will be critical to Miss Richie's case and there is no other expert retained by the defence who can testify in this regard."

Lubell denied the request, however, Jane Robison, a spokeswoman for the Los Angeles County District Attorney's office, confirmed the trial had been postponed for at least a day.

Why postpone?

The commissioner still ordered both the prosecution and defence to attend court yesterday to discuss why the trial should be postponed.

Nicole - who is rumoured to be pregnant - will also have the chance to accept a plea bargain today.

The star was not required to attend because it is a misdemeanour charge.

It is believed her attorney will appear on her behalf to accept or reject the deal. Details of the bargain have not been made public.

If convicted, 25-year-old Nicole, who has pleaded not guilty, faces a minimum sentence of four days in jail with three years of probation because of a previous DUI conviction dating from 2003.