The Minister of Social Development is refusing to label $1 billion of overpayments to beneficiaries as bad debt.

Figures from the Ministry show it's the highest amount of overpayments on record.

But the government says most of the overpayments happened under National's watch.

Social Development Minister Carmel Sepuloni told Mike Hosking overpayments are normal because of the constantly changing circumstances of beneficiaries.

"It's been part of the system since the very beginning, and when you look at this its cumulative over time."

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