The Blackcaps have made an 11th-hour call to uncapped test batsman Glenn Phillips, with a number of key players suffering from an illness ahead of the third test against Australia.
The Auckland batsman flew into Sydney on Thursday night, underlining just how concerned the Blackcaps are, despite downplaying the sickness.
Captain Kane Williamson, batsman Henry Nicholls and all-rounder Mitchell Santner are all suffering from "flu-like symptoms" and haven't trained with the team over the last two days.
Williamson is tipped to play unless his condition worsens, but there is more doubt over Nicholls, whose health is worse.
"We've obviously got a few balls up in the air at the moment and we want to be on the safe side and have options," said New Zealand coach Gary Stead.
"Glenn has been in terrific form this season and has good versatility with where he can bat and the roles he can play.
"He's been around the Blackcaps T20 team for the past couple of years, so should feel comfortable in the environment.
"We're still hopeful Henry and Kane will pull through and we will give them every chance to prove their fitness.
"If one or both are ruled out then we will consider our options, and most importantly how they balance the side for this final test."
Phillips, 23, has played 11 Twenty20 internationals, the most recent in November 2018.
He moved into the test frame with some solid first-class form including a century for New Zealand A against England at Whangarei in November.
If Phillips is selected, he would be the 278th New Zealand test cricketer.
The Blackcaps will confirm their starting XI for the dead-rubber test just before the coin toss at 12pm (NZ time).
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