A surge in demand for beer this summer means Lion breweries is struggling to deliver its products around the North Island.
Lion New Zealand spokesperson Genevieve O'Halloran said sales are up almost 20 percent compared to a year ago, and demand for craft beer is particularly strong.
Panhead sales are up 60 percent, Emersons sales are up 140 percent and the supply of soft drinks is also affected.
"Some of our brands are experiencing levels of demand we've never seen before," Ms O'Halloran said.
"The main issue is the unprecedented warm weather so early in the summer, and the demand this has created for our products."
She said additional logistics experts are on site to address the high levels of demand, and the delivery schedule will be extended with people working nights and weekends until the issue is worked through.
"The South Island is unaffected due to a variety of factors – the more dispersed population, the differently structured supply chain, and of course the Speight’s and Emerson’s breweries making sure Mainlanders are well looked after."