Can the custoidal parent sue the non custodial parent for contempt of court for childsupport arrears?

Yes.  You can file a Motion for Contempt with the amount owed included.  If you have a lawyer, they should have ample experience doing these kinds of filings.  In your motion be sure to ask for the arrears to be made "Executory" so that you can file it with the state or their employer to garnish their wages. You should be able to tell the court, and prove with documentation, the exact amount he/she owes to the penny.  Be aware that IF the other party paid you in cash at some point, they will show up to court and argue that those cash payments constitute child support even if it was a birthday gift. If you're in the New Orleans area and need a lawyer, call us at 504-342-4221.