The tourists were due out of MIQ last night, and will play the Black Caps in the opening match of the five-game series which is being staged in Christchurch tonight.
It is far from ideal preparation, but there is another big game later this year where potentially some leading Black Caps players could find themselves in a similar spot — including Williamson.
New Zealand has qualified for the World Test Championship final which will be played at Lord’s in June.
But there are two tests booked against England earlier that month which could cause some scheduling headaches.
The Indian Premier League final is due to be played in early June.
For any New Zealanders involved in that game, getting to England and through any required quarantine period could mean they miss the two tests leading into the final.
"It is really hard to know [what will happen]," Williamson said.
"Certainly it is not the preferred thing and I know when plans were put in place that was not the idea.
"And then as we’ve seen you can make plans in this day and age and very rarely do they go to plan.
"I think for us it is being able to adapt as quickly as possible. We still have to wait and see when the dates are finalised to truly know what is happening before any decisions are made.
"But the ideal scenario would be that you are available and around for all that cricket, so we will just have to wait and see."
Australia has brought a twenty20 squad to New Zealand which is missing some of the test stars such as David Warner, Steve Smith and Pat Cummins.
But Williamson dismissed suggestions the side has the look of a B team.
"There are still plenty of big names as there always are.
"The depth in Australian cricket is something that is always noted.
"A number of their newer-look players have had a lot of experience playing in other competitions around the world, so we know they are a very strong side and we are looking forward to the challenge."
International T20
New Zealand v Australia
Hagley Oval, 7pm
New Zealand: Martin Guptill, Tim Seifert, Kane Williamson (c), Devon Conway, Glenn Phillips, James Neesham, Kyle Jamieson, Tim Southee, Ish Sodhi, Trent Boult, Hamish Bennett, Mark Chapman, Mitchell Santner.
Australia: Aaron Finch (c), Matthew Wade, Marcus Stoinis, Glenn Maxwell, D'Arcy Short, Mitchell Marsh, Josh Philippe, Daniel Sams, Andrew Tye, Kane Richardson, Adam Zampa, Ashton Agar, Jason Behrendorff, Ben McDermott, Riley Meredith, Tanveer Sangha, Ashton Turner.
