With just a few hours until the state of New Zealand's travel bubble is clarified by the Prime Minister, Air New Zealand has increased the amount of flights on its website.

During the week of April 19, the number of flights across the ditch increase to Sydney from the country's main centres up to five times a day and cost $528 a pop.

Prime Minister Jacinda Ardern is set to announce when the two-way quarantine-free travel will start to Australia at 4pm today.

But a quick search on the country's main airline depicts a bubble likely to coincide with the country's school holidays which begin on April 17 and go through to May 2.

The dates are also strikingly similar to Australian states with most - apart from Tasmania - beginning on April 19.

While flights to Melbourne double - from one a day to two at $498 one way, flights to Perth are also up and running again four days a week - Monday, Wednesday, Friday and Sunday at $819 each.

Flights returning from Perth are slightly more expensive at $891 each.

But it's Sydney where the main bubble appears likely to have formed with flights out of Auckland, Wellington, Christchurch and even Queenstown.

On April 19 there are three flights, before it drops to two flights a day on April 20 and 21, before it increases to four flights on the Thursday and five flights on Friday 23.

Saturday has three flights over from Auckland, while four go over on Sunday.

There are up to three flights a day leaving Queenstown to Sydney, some non-stop direct and from $690 one way.

The Australian reported this morning that a travel bubble with New Zealand was expected to begin either Monday, April 12 or April 19, but going by these flight dates, the latter may prove to be more accurate.

Australian Chamber of Commerce and Industry tourism chief John Hart told the Australian "the 19th was pretty much definite".

"That's what the airlines have been told and they've already started bookings."

New Zealand's tourism sector would be crossing fingers for a start before the country's next long weekend - Anzac Day, April 25.

Airlines will need flights for quarantine-free travellers only, who will then need to pass through an airport without mixing with transit passengers or returnees heading for MIQ.

Dedicated airline and airport staff for quarantine-free travel will also need to be kept from mixing with other airline and airport staff.