The government has pledged that £425m of the £638m contributed by the Big Lottery Fund towards the 2012 Olympic Games will be paid back in accordance with a memorandum of understanding it signed in 2007 with the Mayor of London.
The campaign, intended to make sure all the money is paid back as promised, was prompted by correspondence seen by the DSC that it says indicated the memorandum was being updated in the light of the spending review.
A spokeswoman for the DCMS confirmed that the memorandum of understanding was being updated, but said this would not affect the repayment of funds to the BLF. The government was "fully committed" to making sure that the money would be repaid from the receipts of Olympic Park land sales after the games, she added.
Ben Wittenberg, director of policy at the DSC, said he was surprised at the government's reponse to the campaign but said it would continue until the money was paid back.
"There are questions like how the money will be distributed, how it will be paid back and when," he said. "Some more detail on that would be really helpful."