Te Papa will be closed for a second day after sprinklers doused two of its floors yesterday evening.
Sprinklers were activated in the museum's ground floor and first floor foyers on Wednesday night despite there being no fire.
A Te Papa spokeswoman said collection stores and exhibition areas were not affected and no one was hurt.
Te Papa was closed today, and a team was on site assessing the situation, testing the museum's systems, and looking into what happened, she said.
To continue this, it will also be closed tomorrow.
"We understand it's a real pain for those who planned a trip to Te Papa, and we're sorry for the inconvenience," she said.
"Te Papa is taking a precautionary approach - the safety of people and our collections is paramount.
"With our visitors, or staff and our collections we have a very precious cargo here.
"We need to be completely satisfied that everything is as it should be before we open our doors."
A decision would be made tomorrow on whether the museum would open on Saturday.