The missing ''ducks crossing'' signs were installed in March to help protect ducks, especially ducklings, crossing the busy Ardmore St that runs along the town's lakefront.
The Wanaka woman who persuaded the Queenstown Lakes District Council to install the signs, Karen Neilsen, believes their disappearance is more than a prank, as both were taken.
She is not certain exactly when the signs were taken but has complained to Wanaka police and has searched the lakeshore in case they were discarded there.
Ms Neilsen said the signs had saved ducks' lives.
''They cross there all the time.
''It was only just to make people aware - visitors and out of town people - that we do have ducks wandering and to keep an eye out.''
Ms Neilsen said she would like the council to replace the signs.