Gingerbread, the charity aimed at lone parents, has stated that the huge sum is what is owed by so-called ''non-residential parents'' who are not honouring their financial commitments towards their children.
The hardship that results can frequently mean that everyday expenses like clothes, food and childcare seem almost impossible to meet - and Gingerbread's chief executive said that help was available for the cash-strapped families affected.
"Child maintenance is vital for children in separated families.
Ultimately, the responsibility for paying child maintenance rests with the 'non-residential' parent but the Child Support Agency has to do its job in collecting debts and enforcing payment," said Ms Weir.
"We want to help single parents caring for children to take action to ensure that their arrears are paid," she added.
To this end, a free helpline has been set up on 0808 802 0925 which will advise how best to pursue monies owed.
Meanwhile a specially designated surgery session has been set up by MP Gregg McClymont who is setting time aside next Friday (Nov 12) to
advise single parents on this subject.
He admitted that he was struggling to take in the extent of the cash that is owed.
"The amount of unpaid child maintenance in this constituency is staggering," said the Labour man.
"Sometimes arrears are just unavoidable - but not always. More must be done to enforce liability orders and get maintenance to the children who are due these payments," he added.
The surgery will take place at Mr McClymont's constituency office in Lennox House in Seafar's Lennox Road between 2pm and 4pm. Telephone 457788 for further details.
Statistics published by the Child Support Agency reveal that the
average child maintenance payment ranges from 22 to 33 per week but plenty fail to honour this seemingly straightforward transaction.
For a whopping 1.15 million cases are currently being investigated by a UK wide team of 8000 staff.