"Some suppliers have advised us that they anticipate future disruptions due to supply, whether due to manufacturing or transportation."
She said Pharmac was working closely with them to determine the best approach to manage potential shortages which may include temporary restrictions on dispensing volumes to ensure that all New Zealanders have access to the medicines they need."
"Many stock shortages do not result in stock running out; deciding when to implement restrictions to manage supply and to publicly notify potential impacts to supply is always a judgment call as it may cause an unnecessary run on stock that will result in negative consequences.
Pharmac worked with Medsafe, district health boards, the Pharmacy Guild and other pharmacy-representative groups when deciding what public notice was required and when, Williams said.
Most medicine suppliers under Pharmac contracts were required to keep a minimum stock in New Zealand equal to two months' demand.
Williams said there was typically another four to six weeks' worth of stock in New Zealand across the wholesale and retail supply chain, and many medicines were dispensed three months at a time, so patients have a good volume of supply at home.
"Some Pharmac medicines contracts, for example some oral antibiotics, have a greater minimum stock holding requirement, for example four months."
She said medicine suppliers could source alternatives elsewhere in their own global supply chain or work with competitors to bring in replacement products from other markets.
"Where suppliers go below or think there is the potential that they will go below the minimum level of stock, we expect them to contact us with their management plan for the continuity of supply, whether that be the same stock or an alternative supply.
"We understand that New Zealand experiences fewer out-of-stocks than other countries and we think that this could be due to the number of sole supply arrangements we have.