Dramatic video showed the dome’s flat fabric panels flying in the wind over the River Thames towards Canary Wharf.
London Fire Brigade said firefighters had been called to a “partial roof collapse” at the venue.
Station Commander Chris Kamara, who was at the scene, said: “Firefighters cordoned off the area to ensure no one was injured by any further falling debris.
“There has been no actual collapse or structural damage to the building, but due to the nature of the canvas material which covers The O2, it has come loose in high winds and looks quite dramatic.
Crews have made the scene safe and The O2 is now closed until further notice.”
Tom Henry, 24, was working as a civil engineer consultant from his flat overlooking the O2 told the Standard the hole was getting worse as the wind ripped through the arena.
He said: “My flat is pointed right at it and it just caught my eye this black image flapping, I thought what is that?
“It’s shocking at first, you can start to see it go.”
He added: “I just thought ‘Oh my god it is going to completely rip apart’.
“It’s still going now, the hole is getting bigger.
“I went for a closer look and you could hear the wind whirring through it was being amplified.
“You can see the artwork in the bars on the inside and the catwalk but luckily no-one’s injured.
“There are no emergency services or anyone trying to repair it, it’s probably too risky.
“All these things are probably going to increase with climate change. There were loads of people who came to see taking videos and making calls.”
Witness Mala Sharma told the PA news agency that “more and more parts are getting ripped off”.
image: Peter Parnham