Nebraska state officials are trying to contact more than 430 parents who are owed child support after discovering the Department of Health and Human Services didn't send payments in a timely manner.

Department officials acknowledged Wednesday that some unpaid money has sat in a state account for years — as far back as 1998.

The cases involve divorced parents whose children were in state custody, mostly in foster care. The state collected child-support payments from non-custodial parents and the Department of Children and Family Services used it to pay for services the children received, such as foster care and counseling.

Excess money was supposed to go to the court-ordered payee, usually the custodial parent, but the payments instead remained in a state account. Department officials said it wasn't clear why.

Officials sent letters Wednesday to 431 parents who are collectively owed about $250,000, said Doug Weinberg, director of the state's Children and Family Services Division. The amounts owed to individual parents vary, but average about $500 per person.

Weinberg said the account at one point held about $3 million, but officials have since reduced it to $1.4 million. The 431 parents are the people whose addresses the department has confirmed, he said.

"We've made a concerted effort to identify and locate as many custodial parents as possible," he said.

Doug Kreifels, the division's chief financial officer, said the department has updated its policies to ensure that child-support payments are sent to the proper recipient each month.