Can enforcement proceed against arrears even after the underlying support order has ended?

Yes. The end of a support order or agreement, whether because a child has aged out, the term expired, or the parties otherwise reached the end of the obligation, doesn't erase arrears that built up while support was owing. The debt for unpaid amounts survives the order itself, and the Family Responsibility Office's enforcement tools, including garnishment, licence suspension, property liens, and credit bureau reporting, generally remain available to collect that outstanding debt even though no new support is accruing going forward.

This is an important distinction for both sides to understand: a recipient with old arrears shouldn't assume the debt became uncollectible just because the support term ended, and a payor shouldn't assume that reaching the end of their support obligation clears whatever arrears remain outstanding. The arrears continue to be tracked and enforced as their own matter. Anyone dealing with older arrears from a support order that has otherwise ended should confirm the current balance and enforcement status with FRO, and get legal advice if there's a dispute about how much is actually still owed.