  We study compactifications of type IIA supergravity on six-dimensional
manifolds with SU(2) structure and compute the low-energy effective action in
terms of the non-trivial intrinsic torsion. The consistency with gauged N=4
supergravity is established and the gauge group is determined. Depending on the
structure of the intrinsic torsion, antisymmetric tensor fields can become
massive.
