Welcoming Australians back to New Zealand could result in a billion-dollar boost to our economy if a transtasman bubble opens in the coming weeks.

That's the latest forecasting from Tourism New Zealand (TNZ) before Tuesday's expected opening date announcement.

TNZ interim chief executive Rene de Monchy said it would be very welcome news after a tough year for tourism.

Before Covid-19, Australia was our biggest overseas market, making up about 40 per cent of international visitors.

That accounted for about $2.7 billion a year.

"And by our modelling if Australia opens up in the coming weeks, it could be up to $1 billion and maybe even more that flows into our economy for the rest of this calendar year, so absolutely a big hope for the industry and it allows them to plan for it," de Monchy said.

On average, international visitors also spent two times more than domestic travellers and three times more per day than residents. Without international visitors there was likely to be a $12.9b gap each year in visitor spend, he said.

TNZ has continued to promote New Zealand, but is preparing a new campaign to showcase New Zealand as a destination.

"We think visitors and tourism will probably take a little bit longer to restart and probably as we get into the June-July holiday period and into the October holiday period that's when you'll really see visiting start to ramp up, so we're conscious of that as we think about our marketing plans in Australia," de Monchy said.

"The key thing we've been doing because we haven't been sure on the timing, we've been adjusting that plan over the last months because there was a moment when we thought this travel zone might happen back in October and then back at Christmas, so we've been continually adjusting that plan to the context and we'll be ready to go as soon as an announcement is made."

As for where Australians would travel when the bubble opened up, de Monchy said historically popular destinations were expected to remain so.

"You should see a strong interest and we're seeing it already from Google search trends ... in Queenstown."

He expected Australian visitors would complement domestic travellers for the tourism industry as they travelled further and outside weekends and public holidays.

But there would be some competition to attract Australians as other Australian states would be looking to attract both domestic tourists and New Zealanders, he said.

"It's going to be a really unique competitive environment for the coming months as we both are each other's captive audience."

De Monchy said TNZ would continue to market both domestically and in Australia, and there were more Australians to target than vice versa.

"Last year has been really good domestically, but it's not enough to fill the hole left by international visitors."

Surge in Australians booking NZ holiday homes

New Zealand holiday homeowners are already reporting a surge in bookings from Australia in the lead-up to the bubble date being announced.

Bachcare figures show a 117 per cent increase in speculative bookings over the month before the announcement.

Spokesperson Zaina Razzaq said it showed a marked interest in travellers researching and booking accommodation, despite no confirmation on a quarantine-free travel bubble.

The figures showed beaches, food and wine were high on the list of Australian travellers - whereas in previous years the focus was on ski holidays, she said.

"What is coming through in our research this year is a surprising lack of bookings around New Zealand ski fields such as Queenstown and Ohakune," Razzaq said.

"At this time of year, we would typically be seeing an influx of Australians booking their accommodation for a midwinter ski holiday. Instead, the bookings are concentrated around beaches and vineyards; and feedback we are getting is that a lot of people want to spend time reconnecting with family members living in New Zealand - many of which they have been unable to see for over a year now."

Prime Minister Jacinda Ardern says the Government will announce the commencement date of the transtasman travel bubble on April 6.

The top 10 locations for Australians booking are Raglan, Tauranga, Waiheke, Marlborough, Mount Maunganui, Marlborough Sounds, Martinborough, Akaroa, Whangamatā and Hanmer.

While Queenstown had fewer confirmed bookings that expected, Razzaq said it was the most popular search term, suggesting many were researching and preparing for when the bubble was confirmed.

"What we believe the data is showing us is that Australians looking to travel here for skiing in a specific seasonal time frame are waiting for confirmation of the bubble to open before they book. Conversely, travellers who are more flexible in their travel time frames are making bookings in regions either well known for their wine production such as Waiheke, Marlborough and Martinborough or coastal areas such as Raglan, Tauranga, Mt Maunganui, Akaroa and Whangamatā.

"The most common reason we are hearing from Australians making bookings through us is a desire to beat the rush ahead of the peak season."

By RNZ