The objective of this contribution is input design for accurate identification of non-minimum phase zeros in linear systems. Recently, several variance results regarding estimation of non-minimum phase zeros have been presented. Based on these results, we will show how to design the input that has the least energy content required to keep the variance of an estimated zero below a certain limit. Both analytical and numerical results are presented. A striking fact of the analytical results is that the variance of an estimated zero is independent of the model order when the optimal input is applied. We will also quantify the benefits of using the optimal design compared to using a white input signal or a square-wave. Robustness issues will also be covered in this presentation. The optimal design depends on the location of the true unknown zero and is therefore infeasible. This is typically circumvented by replacing the true zero by an estimate. The sensitivity of the solution to this estimate is investigated.