Chris Goodman said Winehouse, who has struggled with drug and alcohol abuse, "is withdrawing from all scheduled performances" to focus on recovering.
"Everyone involved wishes to do everything they can to help her return to her best and she will be given as long as it takes for this to happen," Goodman said.
He did not disclose the reason for her unsteady appearance in Belgrade.
Winehouse's show on Saturday kicked off what was supposed to be a 12-stop European tour. But she was jeered and booed as she stumbled around the stage, unable to remember the lyrics to her songs.
Serbian media called the concert a "scandal," with the Blic daily labeling it "the worst in the history of Belgrade."
The tour had been due to end in Bucharest on Aug. 15.
Winehouse's breakthrough album, 2006's "Back to Black," won her five Grammy Awards and brought her worldwide stardom,
The album included the hit single, "Rehab," on which she sang: "They tried to make me go to rehab. I said 'No, no, no."'
The song was prophetic: Winehouse's music has been overshadowed by alcohol and drug use and run-ins with the law, as well as a tempestuous marriage to music industry hanger-on Blake Fielder-Civil. The pair married in 2007 but divorced two years later.
The 27-year-old British singer has, in fact, sought rehab therapy in the past. In October, Winehouse said she had been drug-free for three years, but her public behavior has continued to appear erratic.
Last month she spent a week in London's Priory clinic, which offers treatment for psychiatric problems, drug and alcohol addiction.
In addition to her stage troubles, Winehouse's recording career has also been put on hold. There have long been plans for a follow up to "Back to Black," but new material has not been released.