New Zealand Football (NZF) say they have told all players in contention for the All Whites they risk missing out on selection if they are unvaccinated against Covid-19.
The news comes after it was revealed at the weekend that one player had missed selection for a pair of matches in Abu Dhabi this month because they were unvaccinated.
In naming the latest squad on Monday, NZF said they wouldn't be revealing who the unvaccinated player was.
"All of [this] squad are vaccinated against COVID-19, as is required for playing and training in Abu Dhabi.
"New Zealand Football has stressed the importance of vaccination to all players in contention for the team as well as informed them that they risk missing out on future selection if they are unvaccinated.
"New Zealand Football will not be releasing the vaccination status of individual players not selected for the team."
The playing group for a friendly against The Gambia on November 17 and a warmup match against a to-be-confirmed side four days earlier included two uncapped players.
Jamie Searle and Francis de Vries had earned the call-up, while Elliot Collier had earned a recall to the squad, which again featured no New Zealand or Australian-based players due to Covid travel restrictions.
All Whites coach Danny Hay stressed the importance of continuing to build the momentum from the October window, when the team collected back-to-back wins against Curaçao and Bahrain.
"It's great we are able to get together again so quickly after two good performances last month.
"We need to be playing games to develop as a team, especially after such a long break prior to October, so we want to take every opportunity we can.
"These games will allow us to look at a few new players who weren't part of the last window as we continue to build towards FIFA World Cup qualifiers next year."
Veteran defender Winston Reid was unavailable in a playing capacity but was travelling to Abu Dhabi to train with the squad and would also continue in his role mentoring the younger members of the team.
The full 21-man squad is:
Stefan Marinovic (26 Caps) Hapoel Nof HaGalil, Israel
Jamie Searle* (0 Caps) Swansea City, Wales
Michael Woud (3 Caps) Almere City FC, Netherlands
Michael Boxall (35 Caps) Minnesota United, USA
Liberato Cacace (5 Caps) Sint-Truidense VV, Belgium
Francis De Vries* (0 Caps) IFK Värnamo, Sweden
Kelvin Kalua (2 Caps) Eastern Suburbs, New Zealand (currently on trial in Europe)
Niko Kirwan (2 Caps) Padova, Italy
Nando Pijnaker (3 Caps) FC Helsingør (loan from Rio Ave FC), Denmark
Tommy Smith (40 Caps) Colchester United, England
Bill Tuiloma (27 Caps) Portland Timbers, USA
Joe Bell (4 Caps) Viking FK, Norway
Matthew Garbett (2 Caps) Torino, Italy
Sarpreet Singh (7 Caps) SSV Jahn Regensburg (loan from FC Bayern Münich), Germany
Marko Stamenic (2 Caps) HB Køge (on loan from FC Copenhagen), Denmark
Joseph Champness (1 Cap) Giresunspor, Turkey
Elliot Collier (2 Caps) Chicago Fire, USA
Andre de Jong (6 Caps) AmaZulu FC, South Africa
Elijah Just (4 Caps) FC Helsingør, Denmark
Callum McCowatt (3 Caps) FC Helsingør, Denmark
Chris Wood (59 Caps) Burnley FC, England
*Debut senior national team call-up