LOCOG has said it has reclaimed 3,000 tickets from officials who are unlikely to use them, and have sold them to the public today.
In its daily press conference, the 2012 Games organisers said they were approaching national Olympic committees on a "daily, session-by-session basis" in an attempt to ensure that more seats are filled.
It follows widespread reports of empty seats at Olympic venues, including some events that would have easily sold out had all the tickets been made available to the public.
The Prime Minister chaired a COBRA meeting with security and Olympic officials this morning, after which it was confirmed that empty seating was seen as one of the priority issues.
A statement said:
At every Olympic event there are blocks of seating allocated to officials and athletes from various competing nations.
These seats are not ticketed, but LOCOG claims they are making every effort to sell them instead of leaving them unclaimed and empty.
London's Mayor Boris Johnson blamed the empty seats on "bureaucrats who don't turn up to the seats they're allocated". He added that all Olympic Games have issues with empty seats in the early events.
LOCOG did not specify for which events tickets had been made available.
Earlier today, the only events that still had tickets available were basketball, artistic gymnastics and weightlifting.
There were anecdotal reports of empty seats at both the hockey and beach volleyball venues at the Olympic Park and Horse Guard's Parade respectively.
Sir Clive Woodward, the Chef de Mission of Team GB, said that the scale of empty seats was still incomparable with the 2008 Olympics in Beijing.