"A major water main burst this morning with huge consequences," the Free University Medical Centre, a teaching hospital, said in an online statement.
"Crucial ... Assets are affected and steam, warm water and heat supply is unstable, resulting in the decision to close the hospital's nursing section," the statement added.
A major street in front of the hospital was closed and footage shown by the public news broadcaster NOS showed a partially collapsed road.
One of the main transfer hospitals is the capital's Academisch Medisch Centrum (AMC).
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The hospital's evacuation started at around 1100 GMT and included 12 newborn babies and five heart patients, the NOS said, adding 339 patients in total were being transferred.
Evacuation was slowed down by broken-down elevators and many of the patients had to be carried down the stairs, the broadcaster added.
Hospital official Wouter Bos said he hoped clearing the patients would be completed by today.