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Abstract We investigate a minimal neutrino portal dark matter (DM) model where a right-handed neutrino both generates the observed neutrino masses and mediates between the SM and the dark sector, which consists of a fermion and a boson. In contrast to earlier work, we explore regions of the parameter space where DM is produced via freeze-in instead of freeze-out motivated by the small neutrino Yukawa couplings in case of $$\mathcal {O} \left( \mathrm {TeV} \right) $$ OTeV heavy neutrinos. For a non-resonant production of DM, its energy density is independent of the DM mass. Assuming a democratic coupling structure we find $$M_N \approx 10 \, \mathrm {TeV}$$ MN≈10TeV . For the resonant production of DM, we find that it can be produced via freeze-in or freeze-out even with couplings of $$\mathcal {O} (10^{-5} )$$ O(10-5) . However, the measurement of the Lyman-$$\alpha $$ α forest rules out the feeble coupled freeze-out case completely, while the resonant freeze-in production is only viable for $$m_{DM} \gtrsim 3 \, \mathring{keV}$$ mDM≳3keV˚ .