British Olympic swimmers More than half of the 650 ticket sale "sessions" were oversubscribed, London 2012 has revealed
London 2012's director responsible for tickets has rejected complaints that the ballot was unfair and led to unbalanced distribution.
Chris Townsend said that oversubscribed events were balloted for each price category.
In a Daily Telegraph webchat with disappointed sports fans, he also revealed second round tickets would be available for several sports.
Some 1.8 million people applied for the 6.6 million public tickets available.
Mr Townsend said: "The ballot was run on a session basis, a separate ballot was run for each price point that was oversubscribed in the session.
"For example, for the 100m final, five separate ballots were run, one for each price point."
Prices for 100m final tickets ranged between £50 and £725.
Mr Townsend said tickets left over from the ballot stage would be available in the second round of sales starting later this month, including for athletics, boxing, basketball, football, volleyball, hockey and beach volleyball.
They will initially offer unsuccessful first-round ticket applicants the first chance to buy those tickets still available.
It will take place on a first-come, first-served basis with the money paid up front.
The general public will later be able to apply for remaining tickets.
In one webchat question, he was asked why people were not told in advance how many tickets were available in each price band for each session.
The questioner suggested this would have better managed expectations and probably would have resulted in more applications for the less mainstream sports.
Mr Townsend said: "We have received a fantastic response from the public across all sports, including the less mainstream sports.
"We will be releasing further information once the process is complete after 10 June."
London 2012 expects to have collected all payments for tickets released so far by 10 June, even though most have already been taken.
However, buyers will not find out which tickets they have been allocated until 24 June.
More than half of the 650 ticket sale "sessions" were over-subscribed.
Athletes' families are among those disappointed with their ticket orders. Diver Tom Daley tweeted that his mother only got a quarter of the events she applied for, adding "I hope my family get tickets to watch me!!!!"
Also on Twitter, cyclist Bradley Wiggins revealed: "No olympic tickets for the wife and kids to watch Team Pursuit, oh well sorry kids going to have to watch dad on the telly!"
Competitors do receive two tickets for friends and family for each event they participate in but it has emerged that swimmers will only get one because the sport is so popular.
The chief executive of British Swimming, David Sparkes, said he was "working closely with the BOA and Locog to resolve this disparity".