NZealand sweat on Williamson, Nicholls, Santner as bug hits team

New Zealand sweated on the fitness of batting kingpin and captain Kane Williamson Thursday after he and Henry Nicholls missed a second day of training ahead of the final Test against Australia.

Both are battling viral infections as they race to recover for the clash in Sydney, where the visitors are desperate to salvage some pride after being thrashed in the first two Tests.

Spinner Mitchell Santner is also unwell and did not practise on Thursday, with batsman Glenn Phillips making a late dash to Sydney Thursday evening as cover.

"It's up in the air at the moment -- a couple of boys are a little bit crook unfortunately," said opener Tom Latham, filling in for Williamson in his pre-match press conference.

"They're having today off, as well as yesterday, so fingers crossed they'll be right to go tomorrow.

"It's gone around the team a little bit which obviously isn't ideal, but fingers crossed, they're resting up and hopefully they'll wake up tomorrow morning and be good to go."