  Using the coupled-cluster method for infinite lattices and the exact
diagonalization method for finite lattices, we study the influence of an
exchange anisotropy Delta on the ground-state phase diagram of the spin-1/2
frustrated J1-J2 XXZ antiferromagnet on the square lattice. We find that
increasing Delta>1 (i.e. an Ising type easy-axis anisotropy) as well as
decreasing Delta<1 (i.e. an XY type easy-plane anisotropy) both lead to a
monotonic shrinking of the parameter region of the magnetically disordered
quantum phase. Finally, at Delta~1.9 this quantum phase disappears, whereas in
pure XY limit (Delta=0) there is still a narrow region around J2 =0.5J1 where
the quantum paramagnetic ground-state phase exists.
