London 2012 is withdrawing half a million Olympic football tickets from sale but 200 thousand tickets for other sports are to be made available.
Organisers are to reduce capacity at Hampden Park in Glasgow and Cardiff's Millennium Stadium.
Cardiff's upper tier of seats will be closed for some games.
But 200,000 more contingency tickets will be made available for other sports, as well as the 50,000 non-football tickets yet to be sold.
Tickets are still available for sports including athletics, hockey and beach volleyball, while there are still some seats available in the higher price bands for the opening and closing ceremonies.
Games organisers have been dogged by criticism throughout the ticketing sales process with fans frustrated by online delays.