  The minimal seesaw extension of the Standard Model requires two electroweak
singlet fermions in order to accommodate the neutrino oscillation parameters at
tree level. Here we consider a next to minimal extension where light neutrino
masses are generated radiatively by two electroweak fermions: one singlet and
one triplet under SU(2). These should be odd under a parity symmetry and their
mixing gives rise to a stable weakly interactive massive particle dark matter
candidate. For mass in the GeV-TeV range, it reproduces the correct relic
density, and provides an observable signal in nuclear recoil direct detection
experiments. The fermion triplet component of the dark matter has gauge
interactions, making it potentially detectable at present and near future
collider experiments.
