  We have obtained empirical relations between the p-mode frequency shift and
the change in solar activity indices. The empirical relations are determined on
the basis of frequencies obtained from BBSO and GONG stations during solar
cycle 22. These relations are applied to estimate the change in mean frequency
for the cycle 21 and 23. A remarkable agreement between the calculated and
observed frequency shifts for the ascending phase of cycle 23 indicates that
the derived relations are independent of epoch and do not change significantly
from cycle to cycle. We propose that these relations could be used to estimate
the shift in p-mode frequencies for past, present and future solar activity
cycles, if the solar activity index is known. The maximum frequency shift for
cycle 23 is estimated to be 265 \pm 90 nHz corresponding to the predicted
maximum smoothed sunspot number 118.1 \pm 35.
