Pharmac thinks Ritalin should be available in pharmacies by Friday.
Parents of hyperactive children are finding it hard to get the drug because of a widespread shortage across the country.
Pharmac director of operations Sarah Fitt said the limited supply is caused by a delayed overseas shipment.
"We believe it's due a manufacturing problem overseas, but that has now been resolved and there was just a slight delay that stopped it from getting to the country."
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