A federal judge has delayed Martha Stewart's (search) sentencing by three weeks while lawyers for the celebrity homemaker prepare a bid for a new trial.

Sentencing for Stewart and former stockbroker Peter Bacanovic (search), originally set for June 17, was rescheduled for July 8, federal prosecutors and defense lawyers confirmed Monday.

Stewart's lawyers said U.S. District Judge Miriam Goldman Cedarbaum granted the delay to give them time to submit a request for a new trial based on perjury charges filed against a government witness.

Larry Stewart, a Secret Service ink expert, was accused in May of lying eight separate times on the witness stand, mostly during testimony he gave about a worksheet prepared by Bacanovic.

"The motion for a new trial, expected to be made later this week, will contend that the jury was unfairly affected by the alleged perjury of government witness Larry Stewart," Stewart lawyers Robert Morvillo and John J. Tigue said in a statement.

Federal prosecutors had no comment beyond confirming the delay. Cedarbaum's office had no immediate comment.

Martha Stewart and Bacanovic are expected to be sentenced to 10 to 16 months apiece in federal prison for lying about why Stewart sold 3,928 shares of ImClone Systems Inc.  (IMCL) stock in late 2001, just before the price plunged.

Legal experts have said the new-trial request will be a longshot because Larry Stewart's testimony mainly concerned a charge of falsifying documents against Bacanovic — a count on which he was found innocent.

Shares in Stewart's media company, Martha Stewart Living Omnimedia Inc. (MSO), rose as the news became public. The company's stock was up 20 cents, or 2 percent, to $9.58 in late-morning trading on the New York Stock Exchange (search).

Stewart relinquished her seat on the company's board after she and Bacanovic were convicted March 5, but she retained the title of founding editorial director.

A previous new-trial request filed by Stewart and Bacanovic has already been rejected by Cedarbaum. In that request, the pair claimed a juror had lied to get on the 12-person panel that returned the conviction.