In this paper we analyze the X-ray, UV, and optical data of the Seyfert 1.5 galaxy 1H0419-577 with the aim of detecting and studying an ionized-gas outflow. The source was observed simultaneously in the X-rays with XMM-Newton and in the UV with HST-COS. Optical data were also acquired with the XMM-Newton Optical Monitor. We detected a thin, lowly ionized warm absorber (log xi approximate to 0.03, log N-H approximate to 19.9 cm(-2)) in the X-ray spectrum, which is consistent to be produced by the same outflow already detected in the UV. Provided the gas density estimated in the UV, the outflow is consistent to be located in the host galaxy at similar to kpc scale. Narrow emission lines were detected in the X-rays, in the UV and also in the optical spectrum. A single photoionized-gas model cannot account for all the narrow lines emission, indicating that the narrow line region is probably a stratified environment, differing in density and ionization. X-ray lines are unambiguously produced in a more highly ionized gas phase than the one emitting the UV lines. The analysis also suggests that the X-ray emitter may just be a deeper portion of the same gas layer producing the UV lines. Optical lines are probably produced in another disconnected gas system. The different ionization condition and the similar to pc scale location, suggested by the line width for the narrow lines emitters, are evidences against a connection between the warm absorber and the narrow line region in this source.