A pipe under the library blocked, leaving a build-up of sewage that soaked a carpet and meant the library could not reopen until the following day.
Dunedin City Council arts and culture group manager Bernie Hawke said the pipe might have blocked anyway, but the library was having a busy day with passengers from Celebrity Solstice.
Mr Hawke said while toilets in the building, popular with cruise ship passengers for its facilities as well as free Wi-Fi, were flushing, the blockage meant the sewage pooled under the library.
That meant the library had to be closed on Friday afternoon, after ``there was water on the floors which seeped into some carpet''.
Workers were brought in to sanitise and ensure there was no health risk from contaminated material.
The area was cleaned and dried.
``The problem was addressed promptly, and there were no public safety issues,'' he said.
That involved using a drain inspection camera to find the problem, a temporary fix, then plans for the pipe to be fixed permanently ``in the not-too-distant future''.
``That will be rectified as soon as possible.''
Mr Hawke said he understood the library was ``very busy'' on Friday.
On cruise ship days the library was a popular place for people to use the internet on free giga-speed Wi-Fi.
``It is a popular place for people to pop in and get their bearings.''
