Nearly half the parents in St Helens who are required to pay their child maintenance through government intervention in are still failing to pay their ex-partners.
Charity Gingerbread, which supports single parent families, says the current system is not sufficient to deter parents from underpaying or paying late.
New figures from the Department for Work and Pensions show that around 590 parents were due to pay support through the Collect and Pay scheme in St Helens between October and December 2018, covering 830 children.
The Child Maintenance Service is supposed to take money directly from these parents' earnings or their bank account if they try to avoid payments, and can eventually take them to court.
Despite this, 46% had not made any payment in St Helens – up from 42% the previous year.
From October to December, the best payment rate was in the Shetland Islands, in Scotland, where only 25% of parents failed to pay. The poorest record was in Mole Valley, in South West England, where 58% of parents did not meet their financial obligations to their children.
The Child Maintenance Service, which agrees payment of child support with parents, can alternatively calculate the amount of child support to be paid and parents can make the arrangements themselves – a scheme called Direct Pay.
In St Helens, 1,030 parents made Direct Pay arrangements from October to December 2018, covering 1,440 children.
At the end of 2018, two-thirds of parents paying child maintenance in Britain were using Direct Pay and a third the Collect and Pay Service.
Anant Naik, from Gingerbread, said many parents feel frustrated by CMS inaction over outstanding payments.
"These figures are a reality check for the Government and prove that the Child Maintenance Service is failing huge numbers of hard-working single parents.
"Our research has already revealed shortcomings in the system’s design and functionality and that almost seven in 10 single parents are being let down by the Collect and Pay system, meaning they are left to support their children single-handedly.
"Collect and Pay charges must be scrapped for receiving parents, payment compliance must be much more closely monitored for strengthened case management, and transparent service standards should be introduced, backed up by rigorous training for staff."