Police have warned motorists of "significant congestion", in Westgate, Auckland near the new Costco site which opened earlier today.
Motorists are advised to take other routes if they are not going to Costco.
The new store officially opened its doors at 8am, with a ribbon-cutting ceremony held at 7:30am.
A group of fans spent the night camping outside the megastore, with some seen lining up as early as 2pm on Tuesday - and those waiting were very excited.
Fans have travelled from around the country to be in Auckland for the opening, with some coming from Tauranga and Invercargill.
Fans could be seen with Costco shirts and a couple of fans had the logo of the megastore as tattooed on them.
The store sells a wide range of goods including food and grocery items, clothing, electronics, furniture and more.
It will also have warehouse services which include a food court, pharmacy, optometrist, audiologists, tyre service centre and a petrol station that already opened in April.
The $100 million store was initially planned to open in mid-August but shipping, weather and COVID-19-related delays kept the doors shut an extra month.
Earlier this year, thousands of Kiwis queued up for the $60 annual membership that gives access to what is described as a department store inside a hardware store.
