Southee and Williamson grew up playing cricket alongside each other, rising up the ranks from the Under-19 levels to become their country's second-highest wicket-taker and leading run-scorer respectively. The two of them had also played their 50th Test together, against Zimbabwe in 2016, and will join Stephen Fleming, Daniel Vettori, Brendon McCullum and Ross Taylor as the only other New Zealand men with 100 Tests to their name.

"Their achievements at Test level speak for themselves," head coach Gary Stead said, "And they are undoubtedly two of the greatest players to have ever worn the New Zealand Test shirt."

Southee will follow Taylor, Virat Kohli and David Warner as just the fourth player in history to have played 100 matches in each format.

"[Mitchell] is a key member of the group and has proven, with his performances over the past 12 to 18 months, how much value he adds to the Test team," New Zealand selector Sam Wells said. "Daryl will keep focusing on his rehabilitation over the next week and will be fit and ready for the first Test in Wellington."

Mitchell Santner continues as the specialist spin bowling option, while recent Test double-centurion Rachin Ravindra and allrounder Glenn Phillips lending support.