In a method and arrangement for local manipulation of a B.sub.1 field in a first region of an examination subject in an examination volume of a magnetic resonance system, a B.sub.1 measurement value that represents the B.sub.1 field in the sub-volume during an adjustment measurement is integrally determined, and in desired radio-frequency signal parameters for a subsequent magnetic resonance measurement are predetermined on the basis of the determined B.sub.1 measurement value. At least during the adjustment measurement, the B.sub.1 field is influenced within a second region counter to the manipulation intended in the first region by means of an auxiliary coil element which is arranged in or at the second region of the sub-volume remote from the first region.