NEW YORK (CNN/Money) - The U.S. Probation Department is investigating whether Martha Stewart violated the terms of her house arrest when she attended a Time magazine dinner last week, The New York Post reported Sunday.

"We're going to do some investigating to see if this event was directly related to her employment," Chris Stanton, chief federal probation officer for the Southern District of New York, told the Post.

Stanton's office, the Post said, had originally approved Stewart's request to go to the event, which celebrated Time's 100 Most Influential People issue, a list that included Stewart.

Investigators, the Post said, will want to review the nature of the event and the program and compare it to Stewart's written request to attend.

The affair included a 90-minute cocktail party; many celebrities were in attendance. Stanton told the Post that Stewart's attendance must have a "specific and concrete" link to her employment and added that going to a high-profile party simply for publicity or to be seen is "not good enough" justification.

Stewart was sentenced last July to five months in prison, five months of home detention and two years of probation following her conviction a year ago on criminal charges related to a personal stock sale.

Stewart, 63, completed her prison term early last month and has been mostly confined to her Bedford, N.Y. home ever since. She's allowed to leave her property for up to 48 hours per week for select reasons, including for work.

Earlier this month Stewart was denied a request to be freed from home confinement four months before her scheduled August release. Alternatively, Stewart had asked that terms of her detention be relaxed, including the removal of an electronic monitoring device from her ankle.

In a statement to The Post, Martha Stewart spokeswoman Elizabeth Estroff said "when Time Magazine recognizes Martha Stewart, MSLO's founder, as one of the 100 most influential people in the world, our company benefits from that honor. Having Martha present at industry events where she is honored and recognized for her achievements -- whether or not they hand out awards -- is valuable to us."

Martha Stewart Living Omnimedia (Research), the media and merchandising company, has been struggling from steep advertising losses and other revenue shortfalls in the wake of its founder's legal woes.

The company's shares have fallen 45 percent, to about $20.40, after reaching a 52-week high in late February.

See how much Martha made last year