The Government is writing to 52,000 parents to begin closing their Child Support Agency (CSA) arrangements and inform them of potential charges if they cannot come to an informal compromise.
A new agency called Child Maintenance Service will replace the CSA and will collect money on behalf of parents who fail to come to an informal agreement.
However, the Government will now start charging families for this service.
Parents have the option of a family based arrangement - which will cost nothing - or face a £20 charge if they use direct pay.
However, if one parent refuses to pay and the Child Maintenance Service intervenes then both adults will be charged.
More top news
A Muslim teacher, who was denied entry to the US, has told ITV News he was 'distraught' when he was removed from the flight.
The EC president's pricey warning - amid reports of a £56bn Brexit bill - tempered unexpected positivity from the Bank of England governor.
Sutton United substitute goalkeeper Wayne Shaw has offered his resignation after eating a pie during a match.