  A general analysis of possible violation of CP in processes like $\tau \to
K\pi \nu$, for unpolarized $\tau$ is presented. In this paper, we derive the
new contributions to the effective Hamiltonian governs $\vert\Delta S \vert=1$
semileptonic tau decays in the framework of two Higgs doublet model with
generic Yukawa structure and Leptoquarks models. Within these models, we list
all operators, in the effective Hamiltonian and provide analytical expression
for their corresponding Wilson coefficients. Moreover, we analyze the role of
the different contributions, originating from the scalar, vecor and tensor
hadronic currents, in generating direct CP asymmetry in the decay rate of
$\tau^-\to K^-\pi^0\nu_\tau$. We show that non vanishing direct CP asymmetry in
the decay rate of $\tau^-\to K^-\pi^0\nu_\tau$ can be generated due to the
presence of both, the weak phase in the Wilson coefficient corresponding to the
tensor operator and the strong phase difference resulting from the interference
between the form factors expressing the matrix elements of the vector and
tensor hadronic currents. After taking into account all relevant constraints,
we find that the generated direct CP asymmetry is of order $10^{-8}$ which is
several orders of magnitude larger than the standard model prediction. We show
also that, in two Higgs doublet model with generic Yukawa structure , direct
local or non integrated CP violation can be as large as $0.3$ % not far from
experimental possibilities. This kind of asymmetry can be generated due to the
interference between vector and scalar contributions with different weak phases
which is not the case in the SM.
