The Tonga Ministry of Health says it will review security at the country's main hospital, Vaiola Hospital, after a woman was found touring a ward promoting an alternative medicine.
The woman, who hasn't been named, was arrested by police on Monday night after she approached patients in bed and offered them an unknown concoction.
Radio Tonga reports that no patients were harmed, but the woman was interviewed by police, and then released.
The Director of Health, Dr Siale 'Akau'ola, says this is first time a security breach like this has happened at the hospital, but he would cameras installed to improve safety.
He is urging patients and the public to be more vigilant and report anything suspicious.