After empty seats have been spotted at several venues across the opening three days, Locog attributed the problem to public seats allocated for sale abroad, or to accredited members of international sporting federations whose representatives have not turned up.
They have now negotiated the release of some of those seats in response to public anger that venues are not full.
Jackie Brock-Doyle, Locog's director of communications, said: "We talked to the International Federations yesterday, we were able to put back into the pot for sale around 3,000 tickets last night, they have all been sold," she said.
"That includes about 600 for the gymnastics event today and we're going to do that on a day-to-day basis."
The tickets are being sold on the official London 2012 website, but the limited availability and high public demand have made acquiring the tickets difficult.
Locog have also said they will ask teachers and students to fill some of the gaps, along with military personnel helping out with Games security during their time off duty.