  We study the phenomenology of $d=6$ dipole portal operators connecting active
and sterile neutrinos at a futuristic muon collider. These operators can be the
dominant portal between the Standard Model and the New Physics sector in
scenarios in which the active-sterile mixing is suppressed. We identify two
production modes for sterile neutrinos: one proceeding through the exchange of
an $s-$channel electroweak boson and one arising from the fusion of an
electroweak boson with a Standard Model lepton. We study the expected reach on
the operators suppression scale for these different production mechanisms,
showing that the latter offers the best sensitivity and allowing to test a New
Physics scale in the $\sim 10\;$TeV range.
