A deal with West Ham and Newham Council collapsed amid legal challenges, with the Government announcing last week that the stadium would remain in public ownership and be leased out after the 2012 Games.
The London 2012 chairman said: 'I think it was the right decision to cut through the potential for ongoing legal challenge here and, worse than that, ongoing legal challenge that was taxpayer-fuelled.
White Elephant: The battle continues over what shall be done with the Olympic Stadium after the Games
'I do think it is very important that we maintain a commitment to an Olympic legacy and to a mix of tenancies in there - that is a commitment we made and think we should see through.'
London 2012 and Olympic Delivery Authority Executives were appearing at City Hall to answer questions about preparations for the Games.
Assembly member John Biggs said: 'The decision that has been made regarding the stadium is at very high risk of creating a white elephant.'
He also suggested that the unravelling of the stadium deal and the 'continued insistence on the mixture of uses in the legacy is at risk of jeopardising at massive public expenditure' the future of the venue.
A 'more fundamental review' of the options might be considered, he noted.
Lord Coe, a two-time athletics 1500m Olympic champion, also knocked back suggestions that there was not enough demand for athletics at the stadium.
Standing firm: Sebastian Coe continues to fight against critics of the Games
Capacity at the 80,000-seat stadium is set to be shrunk after the Games. Original proposals were that it be a 25,000-seat venue with an athletics track. A football club as a tenant is still possible.
Asked how many people he would expect to attend an athletics event, Lord Coe noted that London was bidding to host the 2017 World Athletics Championships in the belief that there would be full crowds throughout the competition.
Classic one-day international track meetings, such as the Diamond League, showed there was a demand for athletics in Britain, he argued.
Lord Coe said: 'London is now the only city that stages two of those back-to-back. We not only sell out for every one of those meetings but we would also probably be able to sell five times that number of tickets.
Put to use: West Ham were in line to purchase the stadium, but the deal collapsed
'There is no lack of demand for top-class track and field in this country but clearly sitting alongside the use of the stadium for local events, English schools championships and the plethora of events and other competitions that are there.'
It also has to be for community-based used which 'for one of our national sports is not an unreasonable thing to ask for in London,' he said.
A one-day meeting in Brussels or Paris could draw crowds of between 50,000-70,000 people.
Lord Coe added: 'If we had a larger venue we would fill that venue. You have only got to go to Crystal Palace for any of those Diamond League meetings to know how many people turn up on spec hoping to get tickets. Don't run away with the idea that track and field is a sport that is not supported.'
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