An e-mailed statement by Hilton's rep, Dawn Miller, said the 29-year-old was delayed by immigration authorities upon her arrival Tuesday in Japan.
She was scheduled to appear at a news conference in Tokyo on Wednesday to promote her fashion line, but that appearance was apparently canceled.
It was unclear where Hilton was or whether she will continue with her promotional tour. She was scheduled to visit several other countries, including Indonesia and Malaysia.
The trip had been planned before Hilton's arrest last month in Las Vegas after an officer found a small amount of cocaine in her purse. She pleaded guilty Monday to drug possession and obstructing an officer and was placed on informal probation for one year.
The terms of her sentence did not restrict travel overseas.
"Paris was contractually bound to her business trip and didn't want to let down her brands and many Asian fans," the Miller's statement said. "She intended on fulfilling her contract and is trying hard to do the responsible thing, but this is beyond her control. She is very disappointed by tonight's events."