  Przytycki and Sokolov proved that a three-manifold admits a semi-free action
of the finite cyclic group of order $p$ with a circle as the set of fixed
points if and only if $M$ is obtained from the three-sphere by surgery along a
strongly $p-$periodic link $L$. Moreover, if the quotient three-manifold is an
integral homology sphere, then we may assume that $L$ is orbitally separated.
This paper studies the behavior of the coefficients of the Conway polynomial of
such a link. Namely, we prove that if $L$ is a strongly $p$-periodic orbitally
separated link and $p$ is an odd prime, then the coefficient $a_{2i}(L)$ is
congruent to zero modulo $p$ for all $i$ such that $2i<p-1$. \\
