More than 150,00 people visited Air New Zealand's Grabaseat webpage today as the site turned 10.
It offered 1000 tickets for $10 on domestic flights and the airline says most were gone within minutes.
Within one hour of the birthday deals being placed on the site at 9am, 60,000 people had visited, more than double the daily average.
Cut price international flights remain online until midnight.
A Grabaseat spokesman said the flights were available on various dates, some later this year and early next year.
"Just look around the site a bit and you'll find them."
Eager Kiwis were this morning struggling to view the site as it failed to load for some.
Within minutes of the news breaking, seats across the country sold out.
According to the site, flights from Wellington to Christchurch, Dunedin to Wellington, and Queenstown to Wellington were among the flights to have been snapped up.
Annabelle Fowler, general manager of market development and retail sales at Air New Zealand, said Grabaseat had experienced phenomenal growth since its creation in 2006.
More than 28,000 people visit the site on average each day.
"Customers have taken up more than 1.8 million Greenlight Deals over the past 10 years, covering some 840 million kilometres. That's equivalent to more than 1000 return trips to the moon or 23,000 return trips between Auckland and London."
She said it's the spontaneity of Grabaseat that has resonated with people.
"We've had seats sell out in minutes and know the deals have inspired thousands of impromptu getaways and have given many people the chance to see more of family and friends."
Earlier this week Grabaseat took to the streets to celebrate its birthday, planting a large cake in Auckland's Takutai Square in Britomart.
Punters could burrow for birthday surprises including return international and domestic flights for two.
Grabaseat is famous for its inventive promotions, previously pranking customers on April Fools' Day with its 'grab a seat' deal where the website advertised actual furniture including cane chairs and ski lifts, 'Septemperature', where Grabaseat fares were determined by local temperatures during September last year, and offering a range of themed packages with flights as low as $1.