Thousands of Kiwis have flocked to snare cheap domestic flights today as Air New Zealand rolls out its Boxing Day sale.

The national carrier has launched $19 one-way fares on its Grabaseat platform, which is where it sells a limited number of cheap tickets.

After it went live at 9am, thousands of Kiwis were on the site snapping up deals, with some selling within the hour.

Consumers have enjoyed record low fares - mostly on international flights - in recent years due to an increase in the number of airlines flying to and from this country.

But all good things must come to an end and airfares have been tipped to rise.

Stats NZ data in November shows domestic airfares rose 8.1 per cent between the June and September 2018 quarters.

International airfares were up 3.3 per cent in the same period.

One thing putting upward pressure on fares is the price of jet fuel, which makes up about a third of costs for long-haul flights.

Air New Zealand, in late November, said it will cut about $30 million in costs by next May to offset higher fuel costs in the current year.

In an internal note to staff, the airline was looking at ways of coping with the burden of a high fuel cost environment.

Air New Zealand, at the time, said fuel would make up the largest component of operational costs at $1.3 billion this year, up from $987m last year and $827m the year before.

Fuel costs, however, have come down since then.

According to the International Air Transport Association (IATA) jet fuel monitor, global prices are down 0.6 per cent on a year ago and have fallen 11.5 per cent since the middle of last month.

While that will ease the burden on airlines, much higher fuel prices earlier in the year will have taken their toll.