All Black hooker out of Argentina Test

Dane Coles will miss Saturday's Test against Argentina after flying home to be at the side of his partner who is expecting their first child.

NZ's Dane Coles will miss Saturday's Test against Argentina due to the birth of his first child. (AAP)

Hooker Dane Coles is out of the All Blacks' side to face Argentina after leaving the squad to fly home to be at the birth of his first child.

Coles, who has started six of the seven All Blacks Test this year, had hoped to play in Saturday's Test in La Plata before returning home.

But the All Blacks tweeted that Coles has returned to New Zealand to be with his partner Sarah.

She was due to give birth on October 5.

Conrad Smith missed the first Bledisloe Cup match in August after he flew home from Sydney to also be at the birth of his son.

Coles absence means veteran Keven Mealamu is set to start against the Pumas with uncapped Chiefs hooker Nathan Harris in line for a first cap.

The All Blacks side for the Test, already shorn of the injured Ma'a Nonu and Aaron Cruden after he missed the flight to Argentina, is named later on Thursday.