The Black Caps have been dealt a major blow on the eve of the Test series against Australia, with opener Devon Conway ruled out with a thumb injury.

He joins paceman Kyle Jamieson as first-choice Kiwis who will miss the crunch Test, along with Neil Wagner, who retired on Tuesday after being informed he wouldn’t be picked in the side.

Conway suffered the injury while wicketkeeping in the T20 series against Australia last week, consulting specialists in a bid to be fit for the opening Test, which starts on Thursday.

“It’s disappointing for Devon to be ruled out on the eve of an important match,” coach Gary Stead said.

“He’s a class player batting at the top of the order for us, and I know he was really looking forward to this series

Despite plenty of medical assessment on the thumb, the extent of the injury is still not clear, with the Black Caps awaiting a final diagnosis.

On Tuesday, Stead said Conway had trouble holding a bat.

“He’s had a bat in his hand a few times. It’s not comfortable at the moment,” Stead said.

It’s not yet clear who will replace Conway at the top of the order, with Henry Nicholls called into the squad as batting cover.

“It’s nice to have a player of Henry’s calibre to call on,” Stead said. 

“He has plenty of Test experience and covers a number of positions in our batting order.”

Further medical assessment will determine whether the South African-born Conway can join the squad for the second Test in Christchurch.

New Zealand were already coming into the series understrength, with quick Jamieson ruled out long-term with a stress fracture.

The injuries are especially frustrating for the Black Caps, given they have been waiting eight years to face Australia in a home Test series.

Wagner – a long-term irritant of Steve Smith – also won’t be a part of the series, after a shock retirement announcement on Tuesday.

Stead made the agonising call to effectively end Wagner’s international career last week after a lacklustre performance in the second Test against South Africa, telling him he wouldn’t feature against Australia.

Wagner will still be at the Basin, carrying the drinks and enjoying one last week in the national team set-up.