The Ministry of Health has recalled a common brand of antibiotic after glass fragments were found in two bottles.
Up to 100,000 bottles of Actavis Amoxicillin have been recalled.
The ministry said there had been no reports of harm as a result of people taking Actavis the medicine, and the recall was precautionary.
Pharmacists found the fragments while preparing the medicine for patients. It appears the glass broke off the lip of the bottle during the manufacturing process.
Amoxicillin is commonly prescribed for children to treat conditions such as glue ear and chest and skin infections.
The ministry said people who have been prescribed amoxicillin should check if it is the Actavis brand and if so, stop using it and seek a replacement from their GP or pharmacy.
Stewart Jessamine is group manager of Medsafe, the Medicines and Medical Devices Safety Authority.
He told Radio New Zealand's Checkpoint programme that 10,000-20,000 bottles had already been given to patients, and there had been no reports of problems.
But Dr Jessamine said all bottles of Actavis Amoxicillin had to be returned and he did not know when the product would be sold again.
"Until the root cause analysis by the company is completed and they're able to come back to us with information about how and why it happened, and what steps they've taken to minimise the risk of it happening again, these products will remain off the market."