  Target space duality symmetries, which acts on K\"ahler and continuous Wilson
line moduli, of a ${\bf Z}_N$ ($N\not=2$) 2-dimensional subspace of the moduli
space of orbifold compactification are modified to include twisted moduli.
These spaces described by the cosets $SU(n,1)\over SU(n)\times U(1)$ are
$special$ K\"ahler, a fact which is exploited in deriving the extension of tree
level duality transformation to include higher orders of the twisted moduli.
Also, restrictions on these higher order terms are derived.
