Nearly three-quarters of the earliest child trust fund (CTF) vouchers issued have been used by parents to open a CTF account.
Babies are entitled to vouchers for at least £250
In total, about 1.5 million CTF accounts have been opened since launch, said Treasury Minister Ivan Lewis.
If parents who received the vouchers from January 2005 do not open a CTF account in the next few weeks, the Revenue & Customs will do it for them.
Under the scheme, children born after 1 September 2002 get at least £250 each.
Families on low incomes should receive an additional £250.
The money in the CTF cannot be accessed until the child reaches 18.
However, at the age of 16, children will take over the responsibility for managing the accounts themselves.
"The child trust fund will strengthen the saving habit of future generations and ensure that at age 18... every child will have access to a financial asset," Mr Lewis said.