Te Papa has alerted the Museum of Fine Arts in Boston to a leak near its Monet exhibition.
Monet and the Impressionists is on loan from the Boston museum and includes 56 paintings of 19th century French art, including 27 by Claude Monet.
It is believed to be worth up to $1 billion.
Te Papa chief executive Seddon Bennington told Radio New Zealand torrential rain on Friday caused a small leak in the roof at Te Papa but no water touched the paintings.
Mr Bennington said Boston had been told and Te Papa expected to hear back from it in the next few days.