Marmite is back on store shelves today after half a million jars were delivered around the country.
The breakfast spread has been missing from shops since early last year after the February 2011 earthquake damaged Sanitarium's Christchurch factory.
Stores have been able to sell Marmite since midnight.
Sanitarium general manager Pierre van Heerden said 500,000 jars had been made and he hoped that would meet demand.
It was difficult to predict where people would shop so some areas might sell out, he said.
"What we will be doing is encouraging our consumers to go online to our Marmite Facebook page to ask people in their areas [who] know the stock in their stores to let everyone know and then we can hopefully spread the joy around."
New Zealanders buy about 850 tonnes of Marmite every year.