Antiferromangentic resonance (AFMR) in layered Ni-5(TeO3)(4)Br-2 system with a geometrically frustrated Ni2+ (S =1) spin arrangement has been investigated. Temperature dependence of the lowest mode resonant field could be described with a simple two sublattice model, considering different magnetic susceptibilities. The AFMR linewidth follows a power law T-2.8, due to the magnon-magnon scattering processes. (c) 2007 Elsevier B.V. All rights reserved.