  For an electron localized near a finite rectangular step potential under
strong magnetic field we found a profound local reduction of the gap between
neighbouring Landau levels. We investigate under what conditions the effect
persists when the barrier gets smoother. The conclusion is that to get a
substantial gap reduction the barrier gradient has to be larger than
$\hbar\omega_c/a_L$ ($a_L$ is the magnetic length). The sensitivity of the gap
reduction is illustrated using tilted and multiple step barriers and finite
stripe configurations.
