High-field magnetization was measured for typical itinerant-electron metamagnets Lu(Co1-xGax)(2) with x = 0.06 and 0.07 at temperatures from 4.2 to 300 K in pulsed magnetic fields up to 45 T. Landau coefficients A(T), B(T) and C(T) were determined by fitting measured M-H curves to the equation, H = A(T)M + B(T)M-3 + C(T)M-5. The temperature dependence of the Landau coefficients was well explained by the theory of the metamagnetic transition considering the magnetovolume effect. (C) 2003 Elsevier B.V. All rights reserved.