Abstract We compare production of the low mass K π-resonances by K + and K − beams in the non-charge-exchange reactions K ±p → K 0 s π ±p at 10 GeV/ c. High statistics data, obtained with the same apparatus, allow extraction of the K ∗ (890) and K ∗(1420) production amplitudes corresponding to unnatural and natural parity exchange in the t-channel. The NPE-part dominates in both charge states. Its t-dependence shows a strong crossover at t ≈ −0.3 (GeV/ c) 2 for the K ∗(1420). For the K ∗(890) the crossover is weaker but it occurs at the same value of t. This behaviour can be explained by pomeron, f and ω Regge exchange contributions to the NPE amplitude. The UPE amplitudes agree, both in normalisation and t-dependence, with the expectations of π and B exchange as isolated from data for the charge exchange reaction K −p → (K − π +)n.