Injured New Zealand cricketers Trent Boult and Colin de Grandhomme, who sat out the drawn second Test against England, remained in doubt Tuesday for the upcoming series in Australia.
Coach Gary Stead said they were recovering but were yet to prove they were back to full fitness.
Bowling spearhead Boult and all-rounder de Grandhomme both suffered muscle injuries during the first Test against England.
Stead said they have until Friday to prove their fitness with the team departing from Australia the following day.
"I don't know if I'm really confident, but I'm quietly optimistic that they are both tracking where we want them to be," Stead said.
"The plan that we've got for both of them gives them both a chance to be right for the first Test but it's still just a little bit far out to know for sure."
New Zealand will play three Tests in Australia beginning with a day-night match in Perth which starts on December 12.