  A complete and systematic effective field theory analysis of new physics
effects in \bar{f}f -> ZZ and \bar{f}f -> \gamma Z is performed. Results are
presented for the different initial and final-state polarized differential
cross sections in terms of oblique, gauge-fermion and neutral triple gauge
corrections (nTGC). Phenomenological signatures for new physics detection at
the LHC and at future linear colliders are discussed. In comparison to WW
production, they follow a completely different pattern: nTGC only appear at
NNLO in the effective field theory expansion and, accordingly, are extremely
suppressed. However, in the high energy regime, v << \sqrt{s} << 3 TeV, nTGC
are shown to neatly dominate the longitudinal-transversal final-state
polarizations over the standard model background. Their tiny effects get hugely
amplified at energies \sqrt{s} (0.6-1) TeV and can easily generate up to 20%
deviations over the standard model predictions.
