The 400 m (430-yard) Ever Given, leased by Taiwan's Evergreen Marine Corp, is blocking transit through one of the world's busiest shipping channels for oil and grain and other trade linking Asia and Europe.
A spokeswoman for the owner in Japan said that the refloating work was ongoing but that the company did not yet know when the effort would succeed.
"We don't have an estimate for when the work will succeed," she said.