  In this paper we study cosmological application of new agegraphic dark energy
density in the $f(R)$ gravity framework. We employ the new agegraphic model of
dark energy to obtain the equation of state for the new agegraphic energy
density in spatially flat universe. Our calculation show, taking $n<0$, it is
possible to have $w_{\rm \Lambda}$ crossing -1. This implies that one can
generate phantom-like equation of state from a new agegraphic dark energy model
in flat universe in the modified gravity cosmology framework. Also we develop a
reconstruction scheme for the modified gravity with $f(R)$ action.
