  We have investigated single crystals and polycrystals from the series
Nb$_{1-y}$Fe$_{2+y}$, $-0.004 \leq y \leq 0.018$ by electron spin resonance,
muon spin relaxation and M\"ossbauer spectroscopy. Our data establish that at
lowest temperatures all samples exhibit bulk magnetic order. Slight Fe-excess
induces low-moment ferromagnetism, consistent with bulk magnetometry ($\simeq
0.06 ~\mu_B/{\rm Fe}$), Nb--rich and stoichiometric NbFe$_2$ display spin
density wave order with small magnetic moment amplitudes of the order $\sim
0.001 - 0.01 ~\mu_B/{\rm Fe}$. This provides microscopic evidence for a
modulated magnetic state on the border of ferromagnetism in NbFe$_2$.
