Instabilities for the excitation of the dusty plasma modes, namely the dust-acoustic and dust-lower-hybrid waves, due to the free streaming of ion/dust particles in uniformly magnetized dusty plasmas have been examined analytically. Expressions for growth rates and threshold have been presented for different conditions of free streaming beams of either ions, dust grains, or two contrastreaming dust particle beams. The relevance of the present investigation has been pointed out for laboratory as well as space dusty plasmas.