This manuscript discusses about size and shape-selective preparation of Zinc oxide nanomaterials (ZnO NMs) using simple and handy soft jet plasma source. The soft jet was operated in an atmospheric pressure with low energy consumption and utilized ambient air as a feed gas. The plasma synthesized ZnO NMs exhibited variety of surface morphology such as nanorods, nanosheets and micro-size flowers as compared to the conventional low temperature synthesized powders which showed spherical shape. The precursor concentrations and kinds of precursors were strongly influenced into the NMs morphology and possible growth mechanism in the presence of plasma has been proposed. It is suggested here that the soft jet plasma is an effective tool to control size and shape of ZnO NMs especially when the preparations demanding low temperature, surfactant free and cost-effective synthesis. The prepared ZnO NMs were tested for its shape dependent anti-bacterial property against Gram-positive bacteria namely S. Hue and S. parauberis and two Gram-negative bacteria such as E. coli and V. anguillarum. The flower-like ZnO NMs showed more powerful anti-bacterial activity than rod or sheet-like ZnO structures. (C) 2017 Elsevier B.V. All rights reserved.