"Dollar deals available this afternoon include seats in both directions for Auckland-New Plymouth, Auckland-Gisborne, Nelson-Wellington, Christchurch-Wellington and Christchurch-Invercargill," Air NZ said.
Shortly after the first deal was launched at 9am, Air New Zealand's Grabaseat site was struck by technical difficulties as a result of high traffic demand.
The most popular route, from Dunedin to Wellington, sold out within two minutes.
Air New Zealand chief revenue officer Cam Wallace said the insanely low fares attracted huge interest and unprecedented level of traffic.
"Our booking site did slow for a short time this morning under the weight of a phenomenal number of hits.
"For those who want to be first in line when the next big sale drops, we recommend downloading the Grabaseat app, and signing up to our email sales alerts."
Grabaseat is also offering cheap international fares.
Travellers looking for an international getaway can grab $99 one-way flights to Noumea and Niue, $299 one-way fares from Auckland to San Francisco and Houston, and 90 return trips to Shanghai from $649.