These astronauts, Thomas Marshburn and Kayla Barron, were due out of the space lab later that day on Tuesday for a six-and-a-half-hour outing to replace a faulty radio communications antenna.
"NASA has been informed (of a risk) of debris for the space station," the US space agency tweeted.
"Due to the lack of opportunities to properly assess the risk this could pose to astronauts, the teams have decided to postpone the November 30 spacewalk until more information is available," he said. she added.
In mid-November, Russia destroyed one of its own satellites in a missile test, generating a cloud of debris.
This had forced the seven members of the ISS crew to take temporary refuge in their return ships.
It was not clear whether NASA's postponement of Tuesday's spacewalk was due to debris from the Russian space missile test.
The Russians have dismissed US accusations that their test endangered the space station.
US officials said they had not been informed in advance of the anti-satellite missile test, the fourth only to hit a spacecraft from the ground, which generated more than 1,500 spotting orbital debris.
It was to be Kayla Barron's first spacewalk and Thomas Marshburn's fifth.
The two astronauts arrived on the ISS on November 11 aboard SpaceX's Crew Dragon Endurance capsule with NASA's Crew-3 mission for a six-month stay.
© 2021 AFP