WELLINGTON -- Air New Zealand's trans-Tasman ticket sale hit a record high on Tuesday, with tens of thousands of Kiwis and Aussies booking flights across the ditch in the hours after the travel bubble declaration, Air New Zealand announced on Wednesday.

April is shaping up to be the airline's busiest month so far, with flights from Auckland-Sydney, Auckland-Brisbane and Christchurch-Melbourne on 19 April selling out fast. May is coming in at a close second, Air New Zealand Chief Executive Officer Greg Foran said in a statement.

New Zealand Prime Minister Jacinda Ardern on Tuesday announced that Australians will be allowed to enter the country without mandatory quarantine from April 19.

"Auckland-Sydney was our most popular route yesterday, seeing the largest growth in bookings to date. We expect this is a mixture of friends and family making up for a year of missed milestones, and business travellers keen to get moving again," Greg Foran said.

"While a lot of Kiwis are heading across the ditch, there have been really strong bookings for Australians coming to check out New Zealand. Queenstown will see an influx of Aussies in July and September and we expect to see a bigger boost around the country for the July school holidays. It's promising to be a busy ski season for the mountains.

"We've certainly been looking forward to this moment for a few months now, so to finally have the bubble open is terrific. This will be a great boost for the New Zealand economy and tourism sector," Greg Foran said.