  We use Monte Carlo simulations to study multicritical properties of an Ising
metamagnet in an external field. According to the mean field theory
predictions, a three-dimensional layered metamagnet is expected to display a
tricritical point decomposition to a critical endpoint and a bicritical
endpoint, when a ratio between intralayer ferromagnetic and interlayer
antiferromagnetic couplings becomes sufficiently small. Our simulations show no
evidence of such a decomposition and produce a tricritical behaviour even for a
coupling ratio as small as R=0.01.
