  The Dirac approach to constrained systems can be adapted to construct
relativistic invariant theories on a noncommutative (NC) space. As an example,
we propose and discuss relativistic invariant NC particle coupled to
electromagnetic field by means of the standard term $A^\mu\dot x_\mu$. Poincare
invariance implies deformation of the free particle NC algebra in the
interaction theory. The corresponding corrections survive in the
nonrelativistic limit.
