  We show that the Wigner equations describing the continuous spin
representations can be obtained as a limit of massive higher-spin field
equations. The limit involves a suitable scaling of the wave function, the mass
going to zero and the spin to infinity with their product being fixed. The
result allows to transform the Wigner equations to a gauge invariant
Fronsdal-like form. We also give the generalisation of the Wigner equations to
higher dimensions with fields belonging to arbitrary representations of the
massless little group.
