The IOC has reportedly asked whether London would be able to host the 2016 Olympics if Rio de Janeiro is not ready in time.
The organisers are worried that the construction of every venue for the Brazil Games has fallen behind schedule, according to the London Evening Standard.
The report claims that preparations are only 10% complete, compared to London being 60% ready at the same stage four years ago.
However, a spokeswoman for the International Olympic Committee told The Telegraph that moving the Games would be a "non-starter and unfeasible".
London previously stepped in at the last minute in 1908 when an eruption of Mount Vesuvius prevented the Games from taking place in Italy.
