The money will ensure a contractor can continue to provide support services for local authorities that are rolling out centres.
Children's minister Beverley Hughes revealed last week that the "urgent expenditure" was needed to continue the contract with Serco, which heads the Together for Children consortium providing support services.
She said the funding gap emerged because the money to renew the contract was to be approved through the passage of the Children and Young Persons Bill. However, the Bill is not due to receive Royal Assent until later this year - after the Serco contract expires on 30 September.
Hughes said the Bill would put the Secretary of State "under a duty to promote the wellbeing of children", which would enable him to enter such contracts. In the absence of specific statutory authority, spending on the Serco contract has previously come under the Appropriation Act.
A DCSF spokesman said the Treasury had approved the release of £1.5m from the Contingencies Fund to cover September and October, to be repaid once the Bill receives Royal Assent. He said it was "fairly common" for government departments to borrow money in this way.
Liz Railton, programme director of Together for Children, said that it was "business as usual" adding: "We haven't run out of money - the programme is not in difficulty."
She said: "It's purely a technical issue. They just need to release money, which has already been set aside to fund the extension of our contract to 2010. If they don't have the technical remit to pass the money to us as their contractor, we would have to stop working. There would be a gap and we wouldn't have the money to deliver the contract."
Hughes warned: "Disruption of support for local authorities at this stage would threaten the rollout of children's centres at a crucial time when decisions are being taken about where to locate the remaining centres and how to reconfigure existing services in order to achieve universal coverage. It could lead to a delay in families accessing and benefiting from children's centre services."
